A power-line communication method of performing multi-carrier communication with a communication device using a power line as a communication medium, the power-line communication method comprising: a noise detection step (S401, S402, S501, S502) of detecting a noise condition in the communication medium in correspondence to a period synchronized with a power source cycle of the power line; a communication channel decision step (S403, S503) of generating a plurality of communication channels in a time domain in accordance with a comparison result of the noise condition with a predetermined value on the basis of the noise condition detected in the noise detection step (S401, S402, S501, S502); a tone map preparation step (S404, S405, S504, S505) of preparing tone maps corresponding to the plurality of communication channels generated in the communication channel decision step (S403, S503); a communication step (S406, S506) of transmitting and receiving data on the basis of the tone maps prepared in the tone map preparation step (S404, S405, S504, S505); and a communication medium condition variation detection step (S409, S509) of receiving a measurement result of the communication medium from the communication device and detecting a variation in condition of the communication medium, during communication with the communication device in the communication step, wherein when it is detected in the communication medium condition variation detection step (S409, S509) that the condition in the communication medium varies more than a predetermined amount, the communication channel decision step (S403, S503) and the tone map preparation step (S404, S405, S504, S505) are performed again. a noise detection step (S401, S402, S501, S502) of detecting a noise condition in the communication medium in correspondence to a period synchronized with a power source cycle of the power line; a communication channel decision step (S403, S503) of generating a plurality of communication channels in a time domain in accordance with a comparison result of the noise condition with a predetermined value on the basis of the noise condition detected in the noise detection step (S401, S402, S501, S502); a tone map preparation step (S404, S405, S504, S505) of preparing tone maps corresponding to the plurality of communication channels generated in the communication channel decision step (S403, S503); a communication step (S406, S506) of transmitting and receiving data on the basis of the tone maps prepared in the tone map preparation step (S404, S405, S504, S505); and a communication medium condition variation detection step (S409, S509) of receiving a measurement result of the communication medium from the communication device and detecting a variation in condition of the communication medium, during communication with the communication device in the communication step, wherein when it is detected in the communication medium condition variation detection step (S409, S509) that the condition in the communication medium varies more than a predetermined amount, the communication channel decision step (S403, S503) and the tone map preparation step (S404, S405, S504, S505) are performed again.