To provide a fuel supply pump having a bearing structure ensuring assemblability with a drive shaft and having excellent seizure resistance and excellent strength, in the fuel supply pump in which the cam of the drive shaft having the cam and a bearing section except for the cam are supported by bearing bushes.

This fuel supply pump includes: a plunger 35 pressurizing and forcibly feeding fuel in a pressurizing chamber 32; the drive shaft 80 integrally formed with the decentered cam 83; an annular cam ring 90 provided on the outer periphery of the cam, revolving with rotation of the drive shaft, and transmitting driving force from the drive shaft to the plunger; and a housing 2 having a cam chamber 21 storing the cam and cam ring, a shaft hole part rotatably supporting the drive shaft, and a cylinder section 31 reciprocatably supporting the plunger and forming the pressurizing chamber. The drive shaft is journalled from the outside by the bearing bushes 51, 52, 92 provided to the cam ring and shaft hole part. The cam ring 90 provided with the bearing bush 92 is divided at a plurality of portions over the peripheral direction of the cam ring.