PURPOSE: To improve radiating effect by the stirring of air around a radiating fin that is caused by vibrating the radiating fin by means of ultrasonic waves emitted from the source of ultrasonic waves.

CONSTITUTION: A radiator 1 is made of a piezoelectric ceramic material having a superior thermal conductivity, and radiating fins 2 are made at given intervals in the form of a plate. An LSI chip 3 is thermally in contact with the rear surface of the radiator 1. An oscillation power source 4 generates an alternating voltage having a frequency which matches with the natural frequency determined by the intervals and material of the radiating fins 2, and this alternating voltage is supplied to the radiator 1. When the alternating voltage is supplied to the radiator 1, the radiator 1 oscillates itself, and causes micro vibrations. Then, the radiating fins 2 resonate, causing large vibrations. These vibrations stir air around the fins 2, and hence heat generated from the LSI chip 3 is efficiently discharged. Moreover, this renders an air-driving device such as a fan unnecessary, and hence the generation of noise is suppressed, and also the size of a radiating device can be reduced.