PURPOSE: To cope even with different bit lenghts by reading bit lenght data from the second storage part by an address indicating part, dividing parallel data from the corresponding first storage part into bit lengths, and giving an address of the next data outputted by a parallel-serial converting part to the first and the second storage part.

CONSTITUTION: The first storage part 1 stores parallel data having different bit lenghts, and the second storage part 2 stores bit length data corresponding to it. A parallel-serial converting part 3 converts the parallel data from the storage part 1 into serial data. An address indicating part 4 receives the bit length data from the storage part 2, and divides the parallel data of the corresponding storage part 1 into bit lenghts, and gives an address of the next data outputted by the converting part 3 to the storage parts 1 and 2. In this way, since the storage part 2 is arranged to store the bit length data corresponding to the parallel data having different bit lenghts, the serial data can be sent out in response to the parallel data having different bit lenghts.