PURPOSE: To improve the low temperature starting performance without increasing the noise in an intermediate or high speed revolution region by arranging a check valve in an effluence passage for the excessive fuel and adjusting the compression load of an elastic member for urging the check valve in the valve closing direction.

CONSTITUTION: The excessive fuel in a pump chamber 1a is returned into a fuel tank A through a check valve 3 from an effluence hole 2 formed in the upper part of a pump housing 1 and further through an overflow pipe 4. In this case, as for the check valve 3, a valve body 7 is accommodated by being urged by an elastic member 8 so as to be closely fitted onto a valve seat 6, inside a cylindrical valve body 5 formed in an effluence passage 5a. The valve opening pressure of the check valve 3 is controlled by a valve opening pressure control means 9 by adjusting the compression load acting onto the elastic member 8. In other words, the valve opening pressure control means 9 adjusts the compression load of the elastic member 8 through a lever 13, cam 11, and a seat 10 by utilizing the volume variation of a temperature sensitive expansion member 12 according to the variation of the cooling water temperature.