A capacitor includes a capacitor main body having a front surface on which a semiconductor device is to be mounted and a rear surface at which the capacitor main body is to be mounted on a first main surface of a circuit substrate, a plurality of internal electrodes disposed within the capacitor main body, and a plurality of via conductors penetrating the capacitor main body between the front surface and the rear surface and electrically connected to the internal electrodes, wherein the capacitor main body has a first dielectric layer located on a side of the capacitor main body closer to the front surface and a second dielectric layer located on a side of the first dielectric layer closer to the rear surface, the second dielectric layer having a higher thermal expansion coefficient and a higher dielectric constant than the first dielectric layer.