A cutting tool that improves operability by facilitating operation of a lever for operating a clamp mechanism of a guide member is provided. A clamp mechanism is constituted by a clamp pin that protrudes its distal end to the outside of the blade case while penetrating a depth guide and the blade case, a first lever that is connected to the distal end of the clamp pin and directly moves the clamp pin in the axial direction, and a second lever that is connected to the upper portion of the first lever through a connecting pin and has a cam lever. When the second lever is rotated toward the blade case, the cam lever presses the connecting pin to tilt the first lever, whereby the clamp pin is pulled outward. As a result, the depth guide is pressed to the inner surface of the blade case and clamped.