Fuel pump

A fuel pump, comprising:

• a rotor that rotates;
• a pump housing that interposes the rotor from both sides in an axial direction, the pump housing
• defining a rotor housing chamber that rotatably houses the rotor,
• including a joint housing chamber that houses a body portion configured to be fitted with a rotating shaft, and
• including a partition wall;
• and
• an outer circumferential side housing that includes
• a cylindrical portion formed in a cylindrical shape that surrounds the pump housing from an outer circumferential side, and
• a narrowing portion having a diameter that narrows down with respect to a diameter of the cylindrical portion;
• wherein
• fuel is sucked into the rotor housing chamber and then discharged due to the rotor rotating,
• the pump housing includes
• a fuel port that sucks the fuel into and discharges the fuel out of the rotor housing chamber, and
• a sliding surface portion on which the rotor slides,
• an outer circumferential portion of the pump housing includes
• a joining portion joined to the narrowing portion, and
• a recessed portion that is recessed adjacent to the joining portion, the recessed portion allowing the outer circumferential portion to elastically deform, wherein the joining portion and the recess portion are integral components of the outer circumferential portion, and
• the partition wall forms a part of the sliding surface portion and separates the fuel port and the joint housing chamber.