Heat exchange device and power conversion device

A power conversion device comprising:

• a power semiconductor element;
• and
• a heat exchange device that is formed in a substantially rectangular shape and that cools the power semiconductor element,
• the heat exchange device including:
• a fin formation region in which cooling water flows in a transverse direction of the heat exchange device;
• and
• a buffer region formed in a lamination direction and facing the fin formation region, a partition wall being interposed therebetween,
• wherein an inlet and an outlet for the cooling water are respectively formed at at least one of both ends in a longitudinal direction of the heat exchange device,
• a flow path pit connecting the fin formation region and the buffer region is formed in the longitudinal direction at both ends in the transverse direction, and
• the buffer region has a partition that divides the cooling water flowing in from the inlet and the cooling water flowing toward the outlet, and the inlet and the outlet are respectively connected to the fin formation region via the flow path pit.