To provide an axial piston pump or a motor having a structure capable of realizing smooth movement of cylinder blocks and an end cover even when a liquid with viscosity lower than that of oil, including water, is used as working fluid, and of simplifying manufacturing processes.

This axial piston pump or the motor is provided with the cylinder blocks 3, pistons 2, slippers 10 and swash plates 4 inside a casing, and are constituted such that a main shaft 6 is rotated together with the cylinder blocks 3 and the pistons 2, the slippers 10 are slid on faces of the swash plates 4, the pistons 2 are reciprocated inside cylinder bores 3a in the main shaft 6 direction, and ports 3s of the cylinder blocks 3 are alternately communicated with an intake port 1a and a discharge port 1b of the end cover 1. End faces of the cylinder blocks 3 and an end face of the end cover 1 are constituted so as to be directly contacted with and slid on each other. A low-friction and wear-resistant resin layer A is provided for at least part of the end faces of the cylinder blocks 3 and/or the end face of the end cover 1.