A processing load at the time of playing back sound data having a loop part is reduced.A sound data encoding apparatus comprises a block dividing means that divides the sound data into blocks according to predetermined rules, and an encoding means that encodes the blocks in groups of a plurality of consecutive blocks. The block dividing means divides the sound data such that, when encoded blocks encoded by the encoding means are decoded to output decoded blocks, then the loop end position in a block that includes the loop end position in the decoded blocks is nearer to an end of the block than a predetermined position. In detail, input delay dummy data are added ahead of the sound data before dividing the sound data. At the time of outputting the encoded data, loop information is outputted also. The loop information includes the number of samples of the added input delay dummy data, the number of samples corresponding to the encoding delay, the number of samples corresponding to the decoding delay, the start and end positions of the sound data, and the loop start and end positions.