In a pilot-type valve, a valve box enclosing a main valve is arranged in a state wherein same is sandwiched between pipe flanges tightened to one another with bolts. In the pilot-type valve, a pilot valve is used to control a driving force required to operate the main valve to open and close same. In addition, the valve box is flangeless at its connection end portions for connection with the pipe flanges and has an inlet and outlet for a pressurized fluid. A cover flange neck extended upward from the valve box is constricted only at sites on its walls corresponding to adjacent bolts extended between the pipe flanges, so that the cover flange neck can be passed through the interval between these bolts.