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