An electrochemistry apparatus comprises a supporting body and a reaction layer for generating electromotive force. The supporting body is made of a first material. The reaction layer covers the surface of the supporting body and comprises an ion conductive layer, a first film electrode and a second film electrode. The first and the second film electrodes are separately formed on two opposite surfaces of the ion conductive layer. The ion conductive layer is made of a second material having a thermal expansion coefficient approximating to the thermal expansion coefficient of the first material. The second material has an ionic conductivity greater than the ionic conductivity of the first material. The first material has a toughness greater than the second material. The electrochemistry apparatus employs the supporting body with improved toughness and the ion conductive layer with improved ion conductivity, so as to increase sensitivity and thermal shock resistance.