Abstract: A hydraulic pump for an excavator, which comprises a housing having a supporting wall extending therein; a pair of rotary hydraulic cylinders provided in the housing, each of the rotary hydraulic cylinders being provided with a piston which is movable reciprocatingly in the rotary hydraulic cylinder; and a pair of spindles disposed parallel to the rotary hydraulic cylinders, the spindles being connected with each other via a coupler and driving the rotary hydraulic cylinders to rotate about their respective central axes, each of the rotary hydraulic cylinders comprising a swash plate for receiving and guiding the piston, and the swash plate being stationary relative to the respective spindle, wherein the supporting wall comprises a mounting hole, and the coupler is supported in the mounting hole by means of a sliding bearing.