To surely lubricate the contact surface of a swash plate while reducing agitating resistance of oil.

In this machine, a substantially cylindrical collar member 72 is arranged between a motor shaft 17 of a radial piston motor 25 and a through- hole 38b of a motor swash plate 38 arranged on its radially outside. Nine oil holes 72 are formed on the collar member 72 so as to face to two oil holes 17e radially branched from an oil passage 17a formed inside the motor shaft 17. Oil is supplied from the two oil holes 17e to an oil distribution chamber 73 on an inner periphery of the collar member 72, and evenly distributed to a contact surface 38c of the motor swash plate 38. The motor swash plate 38 is lubricated with certainly without being impregnated with oil.