A smart key storage case includes a storage case main body that can shield a signal, a transmission path through which a call signal from an in-vehicle device is radiated into the storage case main body, a switch that conducts/cuts off the transmission path, a radio communication unit that performs data communication with a radio communication terminal, a controller that controls the switch, and a response signal relay section that radiates a response signal from the smart key inside the storage case main body to the outside. When the radio communication terminal is present outside the vehicle, the controller controls the switch so that the call signal transmitted from the in-vehicle device to the inside of the cabin is cut off and the call signal transmitted to the outside of the vehicle is transmitted.