Abstract: There is disclosed a reduced-scale digital data deinterleaver of simple structure. In a preferred embodiment each word is comprised of 32 bits of data, and 32 words form a block. In each block, each word is separated into four phases cyclically. The resulting bit lines and word lines are interchanged to produce interleaved data items. One block of the interleaved data items is written into a RAM. A higher significant address of 5 bits and a lower significant address of 5 bits of the RAM are specified by the higher significant 5 bits and the lower significant 5 bits, respectively, of the output from a counter. Whenever a block of data is written to the RAM the higher significant 5 bits and the lower significant 5 bits are interchanged to produce first and second count signals. Data is read from the specified address, 1 bit at a time and data is written, 1 bit at a time, into the address just from which data was read out.