A first hole is connected through a first fluid chamber to an inflow hole. A first valve seat is formed around the first hole. A second fluid chamber is connected through a second hole to the first hole. An outflow hole is connected to the second fluid chamber. A second valve seat is formed around the second hole. A third valve seat is formed around the outflow hole. A first valve element is movable in the first fluid chamber to make contact with the first valve seat. A second valve element is movable in the second fluid chamber to make contact with the second valve seat or the third valve seat. A biasing member biases the second valve element toward the second valve seat. An outer peripheral passage is formed between an outer periphery of the second valve element and the second housing to enable flow therethrough.