It is the object of the present invention to provide a manufacturing method for a compound semiconductor device capable of removing remaining organic substances without deteriorating a characteristic of the compound semiconductor device, wherein a surface of an i-type AlGaAs schottky layer is cleaned in a state where light is blocked using either one of ozonized (O3) water whose ozone concentration is at most 13 mg/L and hydrogenated (H2) water whose hydrogen ion concentration (pH) is from 6 to 8 inclusive, or using both of the ozonized water and the hydrogenated water after a schottky electrode made of Ti/Al/Ti is evaporated onto the exposed i-type AlGaAs schottky layer and a lift-off operation is performed using a remover.