A testing device of semiconductor devices includes a temperature detector detecting temperatures of semiconductor devices, and a temperature control unit controlling the temperatures of the semiconductor devices based on a detected temperature, in which the temperature control unit includes thermal heads cooling or heating the semiconductor devices, solution pipes through which solutions set to different temperatures flow, and a channel switching part switching whether or not to make the solution flow through the thermal head, and when a test is conducted, the solution flown through the thermal head is switched according to heating amount of the semiconductor device.