The former head of Olympus is taking legal action against the company for unfair dismissal.
Chief executive Michael Woodford was fired last October after just two weeks in the position after highlighting accounting irregularities.
After initially denying the accusations, Olympus eventually admitted that it had hidden losses $US1.5 billion over 20 years.
Mr Woodford, 51, said on Friday, he had ended attempts to return to the camera and medical equipment company and had instructed his lawyers to bring a case in Britain. He said he would be seeking damages.
At the time of the dismissal, Olympus said it was ending his contract because there was a clash of management styles.
Olympus shares fell more than 4% in Tokyo in early trading on Friday. However, they rallied later in the day and closed 2% higher at 1,053 yen.
Olympus is now being investigatedin Japan, Britain and the United States.
Mr Woodford said he would meet next week with the Serious Fraud Office in Britain.