A former member of the rock group Southern All Stars pleaded guilty Thursday to using stimulant drugs and marijuana during his first trial session before the Yokohama District Court.

Prosecutors demanded a prison term of three years and six months for Takashi Omori, who was a guitarist with the group, one of the most popular rock bands in Japan.

The trial was immediately closed, and the sentence is scheduled to be handed down Wednesday.

Omori told the judges that he started using marijuana "out of curiosity" after he left the band, and later he started inhaling stimulants.

Omori was arrested after inhaling stimulants on May 9 at his home in Yokohama's Naka Ward.