A rotary tool includes a motor having an axis of rotation extending in a forward-rearward direction of the rotary tool. A grip part is located below the axis of rotation in an up-down direction that is perpendicular to the forward-rearward direction. A planet gear is configured to be driven by the motor. An internal gear meshes with the planet gear and is movable in the forward-rearward direction to change a speed. A sun gear meshes with the planet gear, and an output shaft is configured to be rotationally driven by the sun gear. A sensor is configured to detect the forward-rearward movement of the internal gear, the sensor being disposed downward of the sun gear in the up-down direction.