A cooling apparatus for a semiconductor module including a semiconductor chip is provided, including; a ceiling plate having a lower surface; a casing portion having a coolant circulation portion and an outer edge portion surrounding the coolant circulation portion, the coolant circulation portion being arranged to face the lower surface of the ceiling plate, and the casing portion being closely attached, directly or indirectly, to a lower surface of the ceiling plate at the outer edge portion; and a cooling fin arranged in the coolant circulation portion, where the ceiling plate and the casing portion have a fastening portion in which the ceiling plate and the outer edge portion are stacked, and the fastening portion fastens the ceiling plate and the casing portion to an external device, and the cooling apparatus further includes a reinforcing member provided between the ceiling plate and the casing portion at the fastening portion.