To facilitate assembly of a lever to an inflow valve, and stabilize an operation without slipping of the inflow valve from the lever after assembly.

The lever 34 is swingably and axially supported on a constant pressure fuel chamber 35 divided by a diaphragm 41. One end of the lever 34 abuts on the diaphragm 41 by force of a spring 31, and the other end of the lever 34 is engaged with the inflow valve 70 so as to open/close an inlet passage 10 of the constant pressure fuel chamber 35. Fuel in the constant pressure fuel chamber 35 is sucked to an intake passage via a fuel supplying passage. One end of the lever 34 is formed of a pair of right and left plate shaped arms 64 protruded in the vertical direction from a boss part 63 having a shaft hole 63a. An opening 68 engaged with an annular assembly groove 72 of the inflow valve 72, and a pair of right and left elastic claw pieces 65 for receiving the assembly groove 72 into the opening 68 while elastically enlarging and for preventing slipping-off of the in flow valve 70, are integrally disposed on a top wall surface 75 arranged between a pair of arms 64.