Please excuse me for correcting you!
The text is understandable and interesting to read, but I tried to improve it a little.
green words are not understandable or in bad order and are followed by suggestion in brackets ()
red words are corrections

Leading Light in the Boneyard (2)

Shin'ichi Sano, a non fiction writer wrote a book about this case called "TEPC OL Murder"; OL is short for Office Lady that is a Japanese-English word means female office workers. In the 1970's the word was created and they were ranked as ancillary staffs for male workers, the tasks given to them were mainly serving tea and making a copy; they were called "girls" at any rage (range) and the situation is not changed so much even now. 

She was the first female to be employed in general positions at TEPC in 1980. Also her father was working there but he had died when she was a colledge student. She had been living with highly-educated parents and her younger sister in a house in the middle of Tokyo. Even after his (her father's) dead she would not hurt for money (she hasn't struggled for money) in a single-female-parent family because it was reported that her annual income at TEPC was over ten million. There is something wrong with calling her just a "girl", she has graduated from a top university and she was employed in a first-class corporation but she has chosen to sell her body in a small dark town on her own will. According to testimonies from people who knew her, the rate of her sex services was from 5,000 yen to 10,000 yen and  she even has made discounts for poor guests. There was price lowering trend  in accordance with  the age of sellers (prostitutes): young girls with thier school uniform; many high or even junior high school girls had sold their sex and the price for their "brand" was higher than adults even though they didn't have any skills. Even so, in that time (in those times) the usual pay rate for prostitution was about 30,000 yen. She had used to make records of her "work" in her diary, bought cheep snacks at CVS and eaten them for dinner on the train back to her place where her mother and sister have been waiting for her. She had kept this routine untill she was killed at the age of 39. 

When the book was published, the writer was given so many letters from female readers saying that "This could happen to me, too. She is me". He said that he was very amazed about their feedback and that he had not expected, there would be something that could not be seen (was overlooked) by males(men); his report has put emphasis on not her life (not on her life) but on the problem of unjust accusation though; it was enough to awake their voice inside. 

On the next note, I will tell you more details and I will refer to an opinion by Chizuko Ueno who is a pioneer in the field of gender studies on this case. 

(Next note will be uploaded in a few days...maybe)

Leading Light in the Boneyard (2)

Shin'ichi Sano, a non fiction writer, wrote a book about this case called "The TEPC OL Murder."; OL is short for Office Lady, which is an Japanese-English loanword, used in Japanese to means a female office workers. In the 1970's, when the expression was coined, and "OLs" were ranked as merely ancillary staffs for male workers, and the tasks given to them were mainly serving tea or making a copies. They were called "girls" at any rage and even now the situation has not changed so much. 

I'm not sure if "rage" is used to mean the male staff often lost their temper at the OLs, or if it's a typo for age. If you mean age, I'd use They were still called "girls" in spite of their age.

She was the first female to be employed in general positions at TEPC in 1980. Also, her father had been working there but he had died while she was still a college student. She had been living with highly-educated parents and her younger sister in a house in the middle of Tokyo, yet even after her father's death she would not want for money in a single-female-parent family because it was reported that her annual income at TEPC was over ten million. There is something wrong with calling her just a "girl", as she had graduated from a top university and was employed in a first-class corporation; yet she had chosen sell her body at her own will in a small dark town. According to testimonies from the people who knew her, her price rate of her sex was from 5,000 yen to 10,000 yen and she had even given discounts to poorer guests. There has been a lowering trend in the dropping age of the sellers, for example young girls in their school uniforms; many high- or even junior high-school girls had sold their sex and the price for their "brand" was higher than adults, even though they didn't have any skills. Even so, at that time the usual pay rate for a prostitute was about 30,000 yen a session. She had used to normally recorded details about her "works" in her diary, bought cheap snacks at CVS and eaten them for dinner on the train back to her place home, where her mother and sister had been would be waiting for her. She had kept up this routine untill she was killed at the age of thirty-nine. 

You changed focus a couple of times in the paragraph, which made it difficult to correct well.  The comment about the general rate and falling age of prostitutes should be in a separate paragraph.

After the book was published, the writer was given received so many (a torrent of?) letters from female readers saying, that "This could happen to me, too. She is me." He said that he was very amazed at their unexpected feedback that he had not expeted; that there could have been something could not be seen by invisible to males. His report had been intended to put emphasis not on her life, but on the problem of unjust accusation though; still it was enough to awake their female readers' voices inside.

Just a couple of corrections to streamline the text. :)

In the next note, I will tell you more details and refer to the opinion of Chizuko Ueno, who is a pioneer in the gender studies field, on this case.

(Next note will be uploaded in a few days...maybe)

Interesting reading! Looking forward to the next part.