The invention discloses a fully automatic hair washer. The hair washer comprises a hemispherical sandwich outer cover provided with an inner cavity having a shape of the northern hemisphere of the earth, a cylindrical shampoo container which is arranged above and combined with (at twelve o'clock position of) the hemispherical sandwich outer cover, a water inlet pipe passing the central hole of the cylindrical shampoo container to the hemispherical sandwich outer cover, a rotary manipulator which is arranged on the hemispherical top point of the inner cavity of the hemispherical sandwich outer cover and can be driven to rotate clockwise or counter-clockwise by a gear driven by a motor, an electric hair dryer which is arranged in the inner cavity of the hemispherical sandwich outer cover and can blow air to the inner cavity of the hemispherical sandwich outer cover by a plurality of air openings arranged on the inner cavity wall of the hemispherical sandwich outer cover, and a water outlet arranged at the bottom end of the inner cavity of the hemispherical sandwich outer cover. The hair washer can save energy and time and meet requirements of people on hair washing, massage, hair care, cleaning, blow-drying, time conservation and labor conservation.