A driver comprising: a striking unit configured to be movable in a first direction (B1) and a second direction (B2) that is opposite to the first direction (B1); a first bias unit configured to move the striking unit in the first direction (B1) so that a fastener is struck by the striking unit ; a second bias unit configured to move the striking unit in the second direction (B2); a storage battery ; a first operational unit configured to be operated by an operator; a second operational unit configured to be pressed against a workpiece to which the fastener is struck; and a control unit configured to move the striking unit in the first direction (B1) by using the first bias unit when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece , wherein the control unit is configured to execute a second driving mode causing the striking unit to perform a driving operation every time when the second operational unit is operated while the first operational unit is operated, and characterised in that : the storage battery is configured to supply the power to the second bias unit ; the control unit is configured to execute a first driving mode causing the striking unit to perform a single driving operation when the control unit detects the operation of the first operational unit after the operation of the second operational unit , and the control unit further includes a limitation mode limiting the second driving mode on the basis of the performance of the storage battery or the movement state of the striking unit , and while the control unit is in the limitation mode, the striking unit is permitted to perform only the single driving operation in the first driving mode or changing from the first driving mode to the second driving mode is prohibited. a striking unit configured to be movable in a first direction (B1) and a second direction (B2) that is opposite to the first direction (B1); a first bias unit configured to move the striking unit in the first direction (B1) so that a fastener is struck by the striking unit ; a second bias unit configured to move the striking unit in the second direction (B2); a storage battery ; a first operational unit configured to be operated by an operator; a second operational unit configured to be pressed against a workpiece to which the fastener is struck; and a control unit configured to move the striking unit in the first direction (B1) by using the first bias unit when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece , wherein the control unit is configured to execute a second driving mode causing the striking unit to perform a driving operation every time when the second operational unit is operated while the first operational unit is operated, and the storage battery is configured to supply the power to the second bias unit ; the control unit is configured to execute a first driving mode causing the striking unit to perform a single driving operation when the control unit detects the operation of the first operational unit after the operation of the second operational unit , and the control unit further includes a limitation mode limiting the second driving mode on the basis of the performance of the storage battery or the movement state of the striking unit , and while the control unit is in the limitation mode, the striking unit is permitted to perform only the single driving operation in the first driving mode or changing from the first driving mode to the second driving mode is prohibited. <EOS>