Heat exchanger for vehicle

A heat exchanger for a vehicle, the vehicle including an engine and a transmission, the heat exchanger comprising:

• a first flow passage through which an engine coolant flows;
• a second flow passage through which an engine oil flows;
• a third flow passage through which a transmission oil flows;
• and
• plural plates that partition the first flow passage, the second flow passage, and the third flow passage,
• wherein
• the first flow passage is configured to allow the engine coolant to be heat-exchanged with both the engine oil in the second flow passage and the transmission oil in the third flow passage via the plates,
• the second flow passage is arranged in the same layer as a layer of the third flow passage,
• the first flow passage is arranged in a different layer from the layer of the second flow passage and the third flow passage,
• the third flow passage is disposed on an upstream side in a flow direction of the engine coolant in the first flow passage, and
• the second flow passage is disposed on a downstream side in the flow direction of the engine coolant in the first flow passage.