A lock-unlock system for a vehicle includes a mobile terminal and an in-vehicle device. The mobile terminal includes a unit to return a first response signal responding to a first request signal, and a unit to return a second response signal responding to a second request signal in response to receiving power supplied by electromagnetic induction induced by the second request signal. The in-vehicle device includes a unit to transmit the first request signal, to execute first verification control for verifying an identification code in the first response signal; a unit to transmit the second request signal, to execute second verification control for verifying an identification code in the second response signal; and a unit to indicate switching from the first verification control to the second verification control if a condition for the switching is satisfied after the first verification control has been started, to the user.