A communication apparatus includes: a communication unit that periodically transmits, with an interval assigned by TDD (Time Division Duplex) being one TDD time slot and a plurality of TDD time slots being one period, a plurality of application packets corresponding to a plurality of serial signals generated by a plurality of applications to a communication partner device; and a transmission control unit that changes, for every one period, a priority of part of application packets corresponding to part of two or more applications of the plurality of applications, the part of application packets being transmitted in at least one specific TDD time slot for transmitting the part of application packets, the plurality of TDD time slots including the at least one specific TDD time slot.