The commercialized taste sensing system is large and can be used only by particular users at limited places. We are developing a portable sensor with the aim of downsizing the conventional taste sensing system. Measurement targets of taste sensor include foods and pharmaceuticals, which are compounds containing many chemical and biochemical substances. Therefore, working and reference electrodes must be rinsed with alcohol to ensure the reproducibility and stability of sensor outputs, requiring physical and chemical durabilities. The prototype portable taste sensor that we fabricated consists of a taste sensor chip and device and is as small as a USB memory for portability, forming a hand-heldtype sensor. For practical application, the sensor chip has a structure that can contain a reference electrode and multiple working electrodes fabricated on a low-cost highly versatile polycarbonate substrate. The taste sensor chip is integrated in the taste sensor device, which can be held in a hand and is connected to a PC to process the measurement data.