An electric tool comprising: a motor serving as a drive source; a reduction mechanical unit reducing and transferring a rotational power of the motor; and a reduction ratio switching means switching a reduction ratio of the reduction mechanical unit, wherein the reduction mechanical unit is formed so as to switch the reduction ratio by using a switching member moving slidably in an axial direction, and a gear member switching an engagement state and a non-engagement state with the switching member in accordance with a slide position in the axial direction of the switching member, wherein the reduction ratio switching means comprises: a gear shift actuator sliding the switching member in the axial direction; a slide position detecting unit detecting the slide position of the switching member; and a control unit starting the gear shift actuator and temporarily modifying the rotational power of the motor in accordance with a detection result of the slide position detecting unit, characterized in that the control unit is configured to, when driving the gear shift actuator and modifying the rotational power temporarily, increase the rotational power, increase the rotational power after decreasing the rotational power once, or repeat the decrease and the increase with a predetermined cycle, and modify a relative rotation speed between the switching member and the gear member in an incomplete state when the control unit determines by the detection result of the slide position detecting unit that the switching member has not moved slidably to a predetermined target position yet and the gear shift is failed. a motor serving as a drive source; a reduction mechanical unit reducing and transferring a rotational power of the motor; and a reduction ratio switching means switching a reduction ratio of the reduction mechanical unit, wherein the reduction mechanical unit is formed so as to switch the reduction ratio by using a switching member moving slidably in an axial direction, and a gear member switching an engagement state and a non-engagement state with the switching member in accordance with a slide position in the axial direction of the switching member, wherein the reduction ratio switching means comprises: a gear shift actuator sliding the switching member in the axial direction; a slide position detecting unit detecting the slide position of the switching member; and a control unit starting the gear shift actuator and temporarily modifying the rotational power of the motor in accordance with a detection result of the slide position detecting unit, characterized in that the control unit is configured to, when driving the gear shift actuator and modifying the rotational power temporarily, increase the rotational power, increase the rotational power after decreasing the rotational power once, or repeat the decrease and the increase with a predetermined cycle, and modify a relative rotation speed between the switching member and the gear member in an incomplete state when the control unit determines by the detection result of the slide position detecting unit that the switching member has not moved slidably to a predetermined target position yet and the gear shift is failed. a gear shift actuator sliding the switching member in the axial direction; a slide position detecting unit detecting the slide position of the switching member; and a control unit starting the gear shift actuator and temporarily modifying the rotational power of the motor in accordance with a detection result of the slide position detecting unit, characterized in that the control unit is configured to, when driving the gear shift actuator and modifying the rotational power temporarily, increase the rotational power, increase the rotational power after decreasing the rotational power once, or repeat the decrease and the increase with a predetermined cycle, and modify a relative rotation speed between the switching member and the gear member in an incomplete state when the control unit determines by the detection result of the slide position detecting unit that the switching member has not moved slidably to a predetermined target position yet and the gear shift is failed.