A vehicular heat management system includes a heat medium circuit, a heat source portion, and a device. A heat medium cooling an engine circulates in the heat medium circuit. The heat source portion heats the heat medium. The device is configured to function and heat the heat medium when the heat medium flowing into the device is at or above a predetermined temperature. When the engine is being warmed up, heat generated by the heat source portion is supplied to the device in preference to the engine. According to this, since the heat generated by the heat source portion is supplied to the device in preference to the engine when the engine is being warmed up, the engine can be warmed up early.