An apparatus for surveillance of bus-bar temperature. At least one insulative holder made of ceramics or a like high heat conductive material holds a bus-bar. A thermistor or a like temperature sensor contacts the insulative holder and a control device remote from the bus-bar compares an output signal of the temperature sensor with a predetermined reference value, or data of a characteristic curve, thereby judging whether or not an abnormal temperature rise occurs or will occur in near future.