PURPOSE: To acquire a fixing device of an electrolytic capacitor whose fixing strength and aseismatic capacity are improved by holding a compressed elastic ring inserted in a body.

CONSTITUTION: This device is provided with a circular body 10 fitting to a body part of an electrolytic capacitor 2 to be fixed, an elastic ring 20 inserted between a tapered surface 14 formed in an inner peripheral surface of a member (chassis) 8 to be fixed to make the electrolytic capacitor 2 pass through or the circular body 10, and the body part of the electrolytic capacitor 2 and a fixing cover 30 fixed to the member 8 covering the circular body 10 and holds the elastic ring 20 compressed.