To solve the problems on a conventional water stop valve with a check valve, that water flow check test for a division pipe passage cannot be performed unless removing the check valve, and if removing the check valve, it is necessary to reset the check valve after completing the test and reconstruct a seal material and it is impossible to check with the water flow test whether the reset check valve is completely sealed or not.

A valve fitting frame 4 is set to clamp the base flange of the check valve 3 which is threaded into a secondary side connection part and fitted at its front end into a body shell part. A clearance between the valve fitting frame and the body shell part is utilized for providing a bypass flow path which communicates with a ball valve element chest 22 through a secondary side water flow path.