To provide a communication circuit where the security of communication data is enhanced by encrypting data based on rearrangement of data bits.

The communication circuit is provided with a clock control circuit 14 that outputs a pulse of one cycle at a rise timing of a clock signal 101 according to bit arrangement stored in a bit arrangement changeover register 13 once per one frame one after another as clock signals 150-153, data registers 110-113 that store data of a data input line 17 by the clock signals 150-153 respectively, tri-state buffers 120-123 that output data in the data registers 110-113 to an output line 18, and a data output register 16 that stores data from the output line 18 at a fall timing of the clock signal 102 and outputs the data to a data output line 19.