A traveling-wave combining array antenna apparatus includes first and second traveling-wave array antennas. The first traveling-wave array antenna has a plurality of antenna elements provided at intervals along a first feeder line, and has a radiating directivity characteristic. The second traveling-wave array antenna has a plurality of antenna elements provided at intervals along a second feeder line, and has a main beam of a half-value width and a radiating directivity characteristic of a side lobe level lower than that of the first traveling-wave array antenna. A transmitting signal is split into two signals, feeding the signals to the first and second traveling-wave array antennas, which are provided so that a variation of main-beam radiating angle of electromagnetic wave of transmitting signal radiated from the first traveling-wave array antenna corresponding to a frequency change, and that of the second traveling-wave array antenna are substantially canceled by each other.