KEYLESS ENTRY SYSTEM

A keyless entry system including multiple portable devices (20) and an in-vehicle device (1) controlling smart lock and smart unlock of a vehicle door is disclosed. The in-vehicle device (1) includes an vehicle-cabin-inside portable determination section (S102), which when locking the vehicle door by the auto-lock function, determines whether or not there is the portable device (20) located inside the vehicle cabin, and a disabled state release section (S104) that releases the disabled states of all of the portable devices (20) when the vehicle-cabin-inside portable determination section (S102) determines that there is no portable device (20) located inside the vehicle cabin.