BATTERY PACK AND WIRELESS LINKING SYSTEM

The present invention maintains compatibility with a power tool having no wireless connection function, and prevents malfunctions due to linked operation. A battery pack that supplies a driving power source to a power tool, said battery pack comprising: a wireless communication unit for communicating wirelessly with an external device; and a control unit that performs a first determination process to determine the state of a wireless communication connection with the external device, wherein when the control unit has determined in the first determination process that wireless communication has been established, the control unit transmits a linking command to the external device, and during a state in which the wireless communication has been established, the control unit can perform a communication connection cancellation process to cancel the wireless communication.