A check valve is provided with a rectilinear flow passage having a liquid inlet and a liquid outlet and allowing a liquid to flow therethrough in one direction, and a first valve body, a first valve seat, a second valve body, and a second valve seat are provided in the rectilinear flow passage. A first drive body is provided in the rectilinear flow passage at a position closer to the liquid inlet than the first valve body so as to be movable in one direction. The first drive body is driven in one direction by the drive mechanism. The drive mechanism is adapted to set the first drive body either to an open state in which the first drive body presses the first valve body toward the liquid outlet side to detach the first valve body from the first valve seat or to a closure state in which the first drive body does not press the first valve body toward the liquid outlet but allows the first valve body to be seated on the first valve seat. A second drive body is provided in the rectilinear flow passage at a position between the first valve body and the second valve body so as to be movable in one direction. When the first drive is set to the open state, the second drive body is pressed by the first valve body toward the liquid outlet to press the second valve body toward the liquid outlet, thereby detaching the second valve body from the second valve seat, and when the first drive body is set to the closure state, the second drive body is moved away from the second valve body to allow the second valve body to be seated on the second valve seat.