A 35-year-old man who killed a convenience store manager last year has appealed his life sentence to the Supreme Court.

Hidekazu Omori is appealing the Tokyo High Court ruling handed down Friday, his lawyers said Tuesday.

The high court overturned an earlier decision by the Tokyo District Court sentencing him to 15 years in prison.

The Tokyo High Court said in its ruling that 15 years' imprisonment was too light.

Omori stole 550 yen worth of merchandise from the convenience store in JR Tokyo Station in July 2002 and stabbed the store manager to avoid being captured.