To resolve problems that a means to restrain increasing of inner pressure of a low pressure chamber 16 as a technique to lower fuel temperature inside the chamber 16 for increasing lubricity by fuel needs a communication passage for guiding fuel of the chamber 16 to a suction side of a feed pump and a regulator valve for opening the passage, causing costs increase.

A turbulence generating means 42 (a notched face) for generating turbulence in a fuel flow returned from a high pressure chamber 14 to the low pressure chamber 16 is formed on a spill-port 30 formed in a pump housing 12. When compressed high temperature fuel is returned to the low pressure chamber 16 through the spill-port 30, the turbulence generating means 42 generates turbulence in the fuel flow and heat of the high temperature fuel is efficiently transferred to the pump housing 12 to lower temperature of the fuel returned to the low pressure chamber 16. A means for maintaining low the fuel temperature of the low pressure chamber 16 (turbulence generating means 42) is the notched face formed on a passage wall face of the spill-port 30 and the number of the part items of the fuel injection pump do not increase to restrain the costs.