An insulated communication system includes a communication controller that sets communication data to a communication symbol through a numeral system and executes insulated communication through an insulator by adopting the communication symbol. The numeral system includes multiple states having a positive state, a negative state and a zero state. The positive state is represented by at least one positive integer, and the negative state is represented by at least one negative integer. The zero state is represented by zero being a level without generating current consumption. An absolute value of the at least one positive integer and an absolute value of the at least one negative integer are identical to each other. The communication controller sets an initial section of the communication data in the communication symbol to the positive state or the negative state, and sets a following section of the communication data to one of the multiple states.