Abstract: A hydraulic pump includes: a valve plate including a suction port and a delivery port; a valve cover to which the valve plate is mounted; and a cylinder block that slides on the valve plate. The valve cover includes a suction passage and a delivery passage. The valve cover includes: a first chamber that communicates with the delivery passage through a communication passage and functions as a Helmholtz resonator; and a second chamber that communicates with the delivery passage, or with the first chamber, through an introduction passage including a restrictor. In the valve cover and the valve plate, a supply passage extends from the second chamber to a bottom dead center-side sealing surface of the valve plate, the bottom dead center-side sealing surface being a surface located between the suction port and the delivery port. The supply passage includes a restrictor.