Former real estate and resort tycoon Yoshiaki Tsutsumi pleaded guilty Thursday to insider trading and falsification of financial reports concerning Seibu Railway Co. shareholdings.

In the first session of his high-profile Tokyo District Court trial, the 71-year-old defendant — once listed by Forbes as the richest man in the world — said he would not contest the charges.

"As the one who headed the Seibu group, I am painfully aware of the responsibility for causing trouble for shareholders and many other people, and I apologize," he told the court.