Engine cooling device

The invention provides an engine cooling device capable of suitably promoting the warm-up of an engine. This device comprises a cooling circuit and a heat-accumulating passage. The cooling circuit is composed of a radiator passage, a bypass passage, and a flow rate control valve 22 for controlling the flow rate of coolant flowing through the bypass passage. The heat-accumulating passage is provided with a heat-accumulating container 16, and constitutes a heat-accumulating circuit for causing coolant in the heat-accumulating container 16 to circulate via an engine E. The cooling device completes the heat-accumulating circuit by connecting the heat-accumulating passage to the cooling circuit to supply the cooling medium in the heat-accumulating container 16 to the body of the engine E, opens the flow rate control valve 22 to increase a flow rate of cooling medium flowing through the bypass passage, then disconnects the heat-accumulating passage from the cooling circuit, and closes the flow rate control valve 22.