A pressure amplifier (1) is described comprising a housing (2) a low pressure chamber (9-12), a high pressure chamber (13-16) and for transmitting means between the low pressure chamber (9-12) and the high pressure chamber (13-16). Such a pressure amplifier should have a compact design. To this end the force transmitting means comprise a rotor (3) arranged in a bore (4) of the housing (2), wherein the rotor (3) comprises a radially extending low pressure wing (5, 6) and a radially extending high pressure wing (7, 8), the low pressure wing (5, 6) together with the housing (2) delimiting the low pressure chamber (9-12) and the high pressure wing (7, 8) together with the housing (2) delimiting the high pressure chamber (13-16), wherein a supply of fluid into the low pressure chamber (9-12) causes a rotation of the rotor (3) and a rotation of the rotor causes a decrease of volume of the high pressure chamber (13-16).