Electric needle scaler and tool holder

A power tool having a hammer mechanism, comprising:

• a tool holder that extends along a driving axis defining a front-rear direction of the power tool, and includes a front end part that is configured to removably hold a tool accessory selected from various kinds of tool accessories;
• a motor including an output shaft that is rotatable around a first rotational axis;
• a driving mechanism that is operably connected to the output shaft and configured to linearly drive the tool accessory held by the tool holder, along the driving axis when the motor is driven;
• a tool body that extends along the driving axis and houses the tool holder, the motor and the driving mechanism;
• a handle that is connected to the tool body and includes a grip part extending in a first direction crossing the driving axis;
• and
• an operation member that is provided on a front side of the grip part and configured to be manually operated by a user to instruct start of the motor;
• wherein:
• the grip part has a first end that is closer to the tool body and a second end that is farther from the tool body, in the first direction;
• and
• the operation member is arranged in a region of the grip part that includes at least a center position of the grip part that is substantially equidistant from the first and second ends in the first direction.