Cells which arrive in random sequence from the asynchronously operating exchange parts are restored into the original by a small amount of hardware. Distributing parts as inputs of a switch fabric manage serial numbers continuous for each destination. The distributing part divides an inputted variable length packet into fixed length cells, adds serial numbers corresponding to destinations to the cells, and outputs the cells to the exchange parts. The respective exchange parts deliver the cells to the objected destinations. Alignment parts as outputs of the switch fabric classify the reception cells by the number of the distributing part, and compare an expected serial number managed by the alignment part with a serial number of the destination (alignment part) of the reception cell. An identical one is stored in an aligned FIFO queue, and cells of from a packet start cell to a packet end cell are taken out.