According to an embodiment, provided is a Bluetooth device comprising a master module and at least one slave module, wherein: the master module operates in an active mode when a mobile communication device is located within a pre-set range and switches to a power saving mode when the mobile communication device deviates from the pre-set range; in the active mode, the master module performs data communication by being connected to the mobile communication device located within the pre-set range and operates the Bluetooth device by periodically exchanging a packet with the slave module; and in the power saving mode, the master module operates in at least one of a first mode in which a packet exchange cycle with the slave module is adjusted from a first interval to a second interval, and a second mode in which a connection between the master module and the slave module is released.