An autonomous mobile robot includes: a sensor that acquire sensing information by sensing at least one of a situation around the autonomous mobile robot and a state of the autonomous mobile robot; storage that stores a first condition; a transmitter; and a processor that, in operation, performs operations including: judging whether the sensing information satisfies the first condition; and controlling the transmitter to output a collision preventing signal to a predetermined range outside of the autonomous mobile robot when it is judged that the sensing information satisfies the first condition. The collision preventing signal is a signal that inhibits a different autonomous mobile robot from entering the predetermined range.