An intra-forecast mode selecting method is provided to select an intra-forecast mode suitable for intra-forecast coding of a coding subject block from intra-forecast modes including a DC intra-forecasting mode based on a difference in forecast between a coding amount of the intra-forecast mode and an intra-forecast. The intra-forecast mode selecting method is comprised of intra-forecast mode selecting means for correcting the coding amount of the DC intra-forecast mode to be equal to that of the other intra-forecast or less to select an intra-forecast mode based on a difference in forecast between the coding amount of the corrected DC intra-forecast and the intra-forecast.