A valve device for high-pressure gas opens and closes a communication hole for communicating a primary pressure chamber, into which the high-pressure gas flows, to a secondary pressure chamber where pressure is lower than that of the primary pressure chamber. The valve device has a valve seat member provided at the communication hole and a valve body that is caused to be seated on and to leave from the valve seat member to open and close the communication hole. The communication hole has an opening connected to the primary pressure chamber. The opening has a reception recess opened toward the primary pressure chamber. In the reception recess is fitted the valve seat member. As a result, the valve device can achieve sufficient sealing ability.