Provided is a vehicle power supply device able to be fixed easily, at a reduced cost, and universally applicable. The vehicle power supply device includes: a case; a battery, disposed in the case; a cover, covering the case; a support, supporting the battery and connected with the cover; and a rivet, connecting the case and the support. A side surface of the case is provided with a case side hole penetrating into the case. The support is provided with a support side hole corresponding to the case side hole. The rivet is inserted into the case side hole and the support side hole to connect the case and the support. The cover is provided with a cover side hole connected with the case by using a bolt.