Disclosed is a handheld tool using a battery pack (1). A positioning hole (118) is provided on the surface of the battery pack, a locking mechanism (31) matching the positioning hole is provided inside the handheld tool for locking or unlocking the battery pack, and an ejection mechanism (32) is further provided inside the handheld tool to work in conjunction with the locking mechanism to eject the battery pack when the battery pack is unlocked. The battery pack of the handheld tool can be completely inserted into a holding portion of the handheld tool, such that the tool can be made smaller. Moreover, the battery pack has a smooth surface and is convenient to carry, such that assembly/disassembly of the battery pack into/from the tool is more convenient. In addition, there is no detached gap between a tool housing and the battery pack on the surface of the tool, such that the appearance of the tool is more aesthetic.