In a wireless system of one embodiment, a first wireless device includes: a first transmitter which transmits an end-of-transmission notification; and a first receiver which receives a change request signal sent from a second wireless device receiving the end-of-transmission notification. The second wireless device includes: a second receiver which receives the end-of-transmission notification; and a second transmitter which transmits a change request signal when the end-of-transmission notification is received. The first transmitter transmits a signal at a longer interval after the first receiver receives the change request signal, and the second transmitter transmits a signal at a shorter interval after the second transmitter transmits the change request signal.