To provide a fuel injection pump 1 capable of preventing seizure of an eccentric cam 21 and a bushing 22 by smoothly supplying lubricating oil.

A communication passage 26 for leading fuel in a cam chamber 10 to a suction side of a feed pump 5 is formed in a cam shaft 2. A communication groove 27 communicating to the communication passage 26 formed on the cam shaft 2 is formed in a pump cover 19 of the feed pump 5, and communication between a suction side of the feed pump 5 and the communication passage 26 of the cam shaft 2 is established via the communication groove 27. Consequently, when pressure in a suction side of the feed pump 5 is kept lower than pressure in the cam chamber 10 by rotation of the cam shaft 2, fuel in the cam chamber 10 flows out to a suction side of the feed pump 5 through the communication passage 26 and the communication groove 27. As a result, since flow of fuel in the cam chamber 10 is accelerated, more lubricating oil is supplied to a slide part of the eccentric cam 21 and the bushing 22 to improve lubricity of the slide part.