An encoding method for producing specific encoded data by calculating the data occupancy of a decoding buffer memory of a particular size that is used when decoding the encoded data during reproduction, defining the allocated code size of a particular period based on the calculation result, and compression coding the signal of a particular period to the allocated code size. The data occupancy is calculated on the assumption that virtual encoded data is transferred to the decoding buffer memory following the transfer of the first-encoded data to the decoding buffer memory. The data occupancy when the last data in the first encoded data is decoded is calculated as the final buffer occupancy Be. The data occupancy when the encoding process producing the second encoded data is begun is an initial buffer occupancy Bi where the initial buffer occupancy Bi is less than the final buffer occupancy Be, and thus allocated code size is defined based on the change in the data occupancy.