To improve the safety of a connecting part, which includes a hose and a metal pipe, by passing the fluid of a high-pressure side to the safe direction when a connecting part is disconnected.

For example, a water passage changing part 4 is provided in an over-low connector 3 of a radiator 1. This water passage changing part 4 is formed by inclining an inner passage 3a of the over-flow connector 3 downward. This inclination is formed by a projecting part 5, which is formed by projecting an upper wall part 6 of the hover-flow connector 3 downward, and an inclined surface 6, which is formed by inclining a lower wall part 3c thereof downward. Consequently, in the case where a reserve hose is disconnected from the over-flow connector 3 by the fitting failure and deterioration of the reserve hose, the over-flowed cooling water is discharged downward like an arrow B. Namely, since the over-flowed cooling water is securely discharged to a ground side different from the projecting direction of the over-flow connector 3, a danger that the over-flowed cooling water is spread on a person is reduced, and the safety can be improved.