To provide a pressure-reducing device that can minutely regulate a pressure and moreover hardly causes water hammer.

In the pressure-reducing device that has coil springs 74, 76 that exert forces on a valve body 5 toward a secondary side, and if the fluid pressure on the secondary side rises, displaces the valve body 5 to a valve seat 7 side against the forces exerted with the coil springs 74, 76 so that the flow rate of the fluid is reduced and the fluid pressure on the secondary side is reduced and regulated, the coil spring 74 of one side is fitted in a spring chamber 72 in a distorted state and the coil spring 76 of other side is fitted in a gap in the spring chamber 72 valve in a free state so that the spring constant of the coil springs 74, 76 is increased as the displacement of the valve body 5 to a primary side increases.