To provide, e.g., a communication system which reduces power consumption.

A communication system includes: a portable machine 20 which has an identification code registered in a vehicle 10 as a controlled object and can conduct wireless communications with the vehicle 10; and a portable terminal 30 which can conduct noncontact wireless communications with the portable machine 20. After noncontact wireless communications start between the portable machine 20 and the portable terminal communication unit 30, the noncontact wireless communications are inhibited when a predetermined condition is satisfied, and then do not resume unless a predetermined instruction is given.