A capacitor module includes a plurality of rounded rectangular prism-shaped capacitor elements and a case housing the capacitor elements. The two capacitor elements are disposed in parallel in the case such that respective first side surfaces of the capacitor elements face each other. The case houses the capacitor elements such that second side surfaces of the capacitor elements face a case inner bottom surface of the case. The second side surface is adjoining the first side surface. The case includes at least one of a protrusion or a hole on the side of a case outer bottom surface of the case at an element boundary portion sandwiched between two rounded corners. The round corners are each provided at a boundary between the first side surface and the second side surface.