To provide a communication apparatus which is mounted on a flying object and is used to communicate with a satellite, which enables the satellite to receive a transmission signal from the flying object at a certain prescribed frequency even if the frequency of the transmission signal significantly changes due to the Doppler effect.

A communication apparatus 10 to be mounted on the flying object and used to communicate with a satellite 20 includes: a transmission unit 5 for transmitting a transmission signal to the satellite 20; a frequency variation acquisition unit 14 that determines the frequency variation of the transmission signal due to the Doppler effect, based on the relative position, attitude, and velocity of the flying object with respect to the satellite 20; and a transmission signal adjustment unit 13 that adjusts the frequency of the transmission signal based on the frequency variation so that the frequency of the transmission signal seen from the satellite 20 is the prescribed frequency.