A drive-in tool comprises a hand-held housing having an energy-transmitting element accommodated therein for transmitting energy to a fastener to be driven in; and a drive apparatus for driving the energy-transmitting element; wherein the drive apparatus comprises an energy accumulator having a gas chamber, which gas chamber can be filled with a driving gas at a defined overpressure, wherein the overpressure in the gas chamber is present as stored driving energy before a drive-in process is triggered, and wherein a piston of the energy-transmitting element forms a variable wall segment of the gas chamber, wherein the gas chamber has at least one further variable wall segment for changing the chamber volume, wherein a movement of the variable wall segment that enlarges the chamber volume charges a mechanical energy accumulator.