A valve device includes a first passage opened by a first valve member, a second passage opened by a second valve member, and a specific chamber in which an asymmetrical state is caused. When the second valve member is open, escape fluid flows through the specific chamber just before flowing into a second passage and collides a collision part located in the specific chamber. The escape fluid flowing in the specific chamber collides the collision part and is divided into two divided flows, and the two divided flows are joined again at downstream of the collision part. In the asymmetrical state, a difference is caused in a pressure loss between the two divided flows. By the asymmetrical state, a pressure loss as an entire of the specific chamber decreases, and frequency in using a valve mechanism can be reduced. Therefore, the valve mechanism can be used longer without omitting the specific chamber.