To compactly integrate a mixing function for mixing two kinds of liquid at a specific mixture ratio with a discharging function and to mechanically and automatically control a discharge amount of the mixed liquid.

A plunger 20 inserted into a solenoid 13 is urged by a spring 22 to an opposite direction to a driving direction of the solenoid 13 when the solenoid 13 is supplied with a current. On both axial sides of the solenoid 13, two pump chambers 18, 19 are disposed to suck/discharge fuel and oil by reciprocating motion of the plunger 20. On a side of discharge ports 26, 34 of the pump chambers 18, 19, a mixing chamber 38 is disposed to discharge the fuel and oil discharged from the pump chambers 18, 19 while mixing them. When load pressure applied to the pump chamber 18 increases to overcome the repulsive force of the spring 22, the plunger 2 is pressed down and fixed at a position at the time when the solenoid 13 is energized. Then, operation of the pumps 24, 32 stops to automatically prevents excessive supply of oil-mixed fuel.