To provide an inexpensive check valve preventing a chattering phenomenon of a disc-like valve element quickly repeating valve opening and closing, and preventing valve closing delay.

An inlet 4, a valve chamber 3, and an outlet 5 are formed in a casing comprised of a body 1 and a lid member 2. An annular valve seat 8 is provided between the inlet 4 and the valve chamber 3. The disc-like valve element 6 opening and closing the annular valve seat 8 is arranged in the valve chamber 3. A protruding part 9 used as a fluid resistance part is provided on a lower end face of the disc-like valve element 6. A coil spring 7 with uneven pitch is attached for energizing the disc-like valve element 6 toward an annular valve seat 8 side. When fluid flows in from the inlet 4, the disc-like valve element 6 is opened against spring energizing force of the coil spring 7, and the fluid is sent down toward an outlet 5 side. When a reverse flow from the outlet 5 to an inlet 4 side occurs, by immediately seating the disc-like valve element 6 on the annular valve seat 8, the reverse flow is prevented.