A communication apparatus according to the present invention includes a power supply that acquires a supply voltage from a power line connected from outside, a transmission control unit that transmits a pilot signal and signals subsequent to the pilot signal to the power line, a pilot signal detection unit that detects pilot signals transmitted to the power line by other apparatuses, and a timing adjustment unit that adjusts transmission timing of the pilot signal of the communication apparatus in accordance with that of the pilot signals transmitted by the other apparatuses.