A movable storage device combined with a smart card can include a plurality of signal pins that are connected to at least one of a plurality of memory card hosts that use different communications protocols from each other or a smart card host, and at least one signal pin that is used as a mode distinguishing pin. A mode deciding unit can decide on an operation mode, which can be a smart card mode and/or a memory card mode based on a level of a first initial input signal received from the mode distinguishing pin. A smart card module can communicate with a smart card host in a smart card mode and a memory card module can be interfaced with memory card hosts, and communicates with a memory card host connected in a memory card mode and stores data.