The utility model provides a reciprocating motion tool. The reciprocating motion tool can reduce torque in the circumferential direction generated when the center of gravity of a shell serves as the center. The reciprocating motion tool is provided with a power transmission part, a tool body and a dynamic vibration absorber. The power transmission part is used for transmitting power of a power source to a front-end tool. The tool body is capable of supporting the front-end tool in a reciprocating motion mode. The dynamic vibration absorber is arranged on the tool body and used for reducing torque in the circumferential direction generated when the center of gravity of the tool body serves as the center and when at least one of the power transmission part and the front-end tool conducts reciprocating motion in the regulated direction. By the adoption of the reciprocating motion tool, when the power of the power source is transmitted to the front-end tool, the torque in the circumferential direction generated when the center of gravity of the tool body serves as the center can be reduced.