A condenser for a power module combines a plurality of aluminum materials to form a casing equipped with a channel for coolant therein, thus making it possible to keep material costs low. Moreover, thanks to the excellent workability of the aluminum materials, it is possible to adopt a configuration with a complex concave-convex configuration for a superior heat radiation performance. A channel for coolant with high heat radiation performance can also be structured inside the casing. The relatively thick bottom plate secures the rigidity required by the casing, while the relatively thin top plate can have a rigidity intentionally structured lower. In this manner, stress generated on joining surfaces of the condenser and an insulative substrate can be mitigated due to active deformation of the top plate.