A picture signal processing method and apparatus in which the block distortion as well as the mosquito noise produced on encoding/decoding a picture is to be suppressed. The picture signal processing apparatus includes a filter for filtering a picture, an encoder 5 for block-encoding the picture, a decoder 13 for decoding an encoded picture from the encoder 5 and a noise reducing unit 14 for reducing at least the block distortion of a picture decoded by the decoding unit 13 to reduce the noise otherwise produced on encoding/decoding the picture.