An AC/DC converter of a power conversion apparatus includes filters, a PFC circuit, a first full bridge circuit, a first transformer, and a first rectifier circuit and converts an AC voltage supplied from the outside to a DC voltage. A DC/DC converter includes filters, a second full bridge circuit, a second transformer, and a second rectifier circuit and lowers a DC voltage output from the AC/DC converter. Constituent circuits of the AC/DC converter located on the primary side of the first transformer are mounted on the upper face of a cooling chassis which cools both the converters. Constituent circuits of the AC/DC converter located on the secondary side of the first transformer and constituent circuits of the DC/DC converter are mounted on the lower face of the cooling chassis.