A communication apparatus includes: a data generating unit that generates write data to be sent to any other communication apparatus at an arbitrary timing; a communication unit that repeatedly sends a read request to the other communication apparatus until the write data is generated and, at the same time, repeatedly receives a read response sent from the other communication apparatus in response to the read request; and a data acquisition unit that acquires read data, which is sent along with the read response by the other communication apparatus, when the read data is generated at an arbitrary timing by the other communication apparatus.