PURPOSE: To easily add an optional delay to each input cell for a communication equipment for an asynchronous transfer mode.

CONSTITUTION: A time stamp ts is calculated to an input cell from the sum of the delay value dy to be added and acquired from a delay value generating circuit 1 and the present time tm obtained from a clock circuit 2. Then the time stamp ts and the input cell are written in a cell buffer 4. At the reading side, a comparator 5 reads a time stamp ts' out of the buffer 4. Then a cell output-enable signal cs is outputted when the time tm exceeds the time stamp ts', and a cell is outputted from the buffer 4.