A wearable device includes a communication unit that wirelessly communicates with a first external device; a motion sensor that senses the user's motion; and a control unit. The wearable device collects a first motion data generated by the user's motion and transmits the first motion data to the first external device, receives a first security level data and a second security level data from the first external device, and receives only the first security level data from the first external device when the wearable device is converted into a non-wearing state from a wearing state.