The invention relates to a power tool that can be held with one hand for reversing, comprising: a casing having a grip part and a manipulation port; a driving device having a control member; the control member is capable of controlling an actuation direction of the driving device; a power source disposed below the driving device and capable of driving the driving device; a reversing assembly disposed at a periphery of the power source and having a reversing member; the reversing member controls the control member to generate changes of displacement, a driving direction of the driving device is changed by action of turning the reversing assembly that is away from the driving device, and there is an appropriate manipulating distance between the grip part and the manipulation port, so that a user is capable of manipulating by holding and reversing the power tool with one hand at a same position.