Patent ID: 7569957

Claim:
A heat generating member cooling structure in which a coolant space is formed between a heat releasing surface that is thermally connected to a heat generating member and an opposing surface that is positioned opposite the heat releasing surface, comprising: a plurality of heat releasing fins that are provided within the coolant space so as to be parallel to one another and stand from the heat releasing surface toward the opposing surface, and an inter-fin passage, through which a coolant flows, formed between every two of the plurality of heat releasing fins that are positioned adjacent to each other, wherein: the heat generating member cooling structure comprises an inflow-side coolant reservoir that extends in a direction in which inter-fin passages are arranged in a row with the inflow-side coolant reservoir connected to ends of the inter-fin passages on a first side so as to allow communication there between, the inter-fin passages and the inflow-side coolant reservoir are joined together so as to allow communication there between by a narrowed portion that extends at least throughout an area in which the inter-fin passages are arranged in the row, and the narrowed portion has a flowing resistance that is larger than a flowing resistance in the inflow-side coolant reservoir.