Thermodynamic relay

A thermal relay (1) includes, in a housing, thermal elements (8a-8c) corresponding to respective phases of a main circuit, a displacer (9) that engages with an operation portion (16b) of the thermal elements and is slidable, and a contact inversion mechanism (14) that switches a contact (13) in conjunction with the sliding of the displacer. The thermal actuator is provided with: a long plate-shaped bimetal (16) which does not serve as an energization path for a main circuit, and which is provided with an operation part that engages with the displacer at the end in the longitudinal direction; and a heater (17) serving as an energization path of the main circuit, the heater having a first heating portion (17c) extending in the longitudinal direction in a state of being in surface contact with the side surface of the bimetal, the first heating portion transferring heat to the bimetal by an overload current flowing therethrough. 本发明的热动继电器(1)在壳体内具有：与主电路的各相对应的热动元件(8a)～(8c)、与热动元件的操作部(16b)卡合并能够滑动的移位件(9)、以及与移位件的滑动联动来切