A pressure detector is disclosed having an organic transistor, a pressure-detecting layer and a first electrode. The organic transistor includes an emitter, an organic layer, a grid formed with holes, and a collector, the organic layer being sandwiched between the emitter and the collector. The pressure-detecting layer is formed on the organic transistor such that the collector is sandwiched between the organic layer and the pressure-detecting layer. The first electrode is formed on the pressure-detecting layer such that the pressure-detecting layer is sandwiched between the collector and the first electrode. The area of the active region of the pressure detector is determined by the overlapped area of the electrodes, thereby reducing the pitch of the electrodes and thus the size of the pressure detector.