To obtain a valve apparatus that can reduce throttle pressure loss by making valve opening large and that can perform rapid closing.

This valve apparatus is provided with a valve main body 11; a valve body 14 accommodated inside the valve main body 11; a valve seat 13 provided inside the valve main body 11 to contact the valve body 14 when a valve is closed; a valve rod 15, which is connected to the valve body 14 and whose sliding portion passes through a valve lid 12 mounted on the valve main body 11; a valve cylinder 17, which stores a piston 16 connected to the valve rod 15 and moves the valve body 14 to the valve seat 13 for opening and closing by the movement of the piston 16 via the valve rod 15; and a closing spring 50, which is arranged inside the cylinder 17 and includes a first spring 21 and a second spring 23. The entire spring constant of the closing spring 50 is configured to become larger when the valve is opened further from predetermined midway opening than when the valve is opened from a totally closed state.