High performance vertical-type organic transistors were fabricated using a simple structure composed of organic/metal/organic layers. This device could modulate a sheet current between emitter and collector by a voltage application to the thin metal base electrode inserted in between. When C₆₀ and perylene derivatives were used for the channel layer, the modulated collector current exceeded 300 mA/cm² by applying only several volts of base voltage, and cut-off frequency exhibited 2.6kHz. The operating mechanism for this device was discussed from the viewpoint of metal base transistors.