Upper arm connection sections and lower arm connection sections are provided in parallel. An upper arm transformer and a power supply are provided in an area opposed to the lower arm connection sections with respect to the upper arm connection sections. A power supply control section is provided in at least one of an area opposed to the upper arm connection sections with respect to the upper arm transformer, and an area which is sandwiched between at least one of the upper and lower connection sections closest to one side of the substrate positioned in a direction in which the upper arm connection sections are arranged, and the one side. The lower arm transformer is provided in an area opposed to the upper arm connection sections with respect to the lower arm connection sections. The lower arm transformer is common to at least two of the lower arm switching elements.