A method and apparatus for encoding a picture advantageously employed for encoding a picture. A plurality of input picture data are stored, and the quantity of the information of the input picture data from the plural stored picture data is evaluated for detecting a scene change. A GOP of a preset unit length, made up of a picture formed by compression by intra-frame coding and a picture formed by compression by inter-frame predictive coding, is selected based upon a scene change detection output and the input picture data is encoded in a pre-set manner in accordance with the selected GOP. By detecting a scene change and selecting the intra-frame coding as a compression method responsive to scene change detection, the compression efficiency is raised at a scene change portion of the input picture data where the correlation between previous and succeeding pictures is lowered.