To provide a power line carrier communication system suppressing an increase rate of a delay time with respect to an increase in repeaters.

The power line carrier communication system includes: a plurality of communication instruments connected by a power line; and at least one repeater between each communication zone formed by dividing communication between the communication instruments into a plurality of communication zones. In the power line carrier communication system, the repeater performs a communication while simultaneously using a plurality of channels having different communication capacities, allocates the channels based on a data amount of communication data, and transmits/receives the communication data for the unit of a much longer time slot for the channel having the greater communication capacity.