An optical fiber cutter for cutting an optical fiber, the optical fiber cutter comprising: a cutter base having a fiber guide part for positioning the optical fiber; a slider, movably attached to the cutter base, having a blade member for incising the optical fiber; a cutter lid attached openably and closably to the cutter base; and an angle switching means for switching an opening angle of the cutter lid with respect to the cutter base, characterized in that the opening angle switching means has a switcher provided on the cutter base and a stopper adapted to operate in conjunction with the switcher so as to engage the cutter lid when the switcher is at a predetermined position; the opening angle switching means further has a switching plate arranged at a rear end part of the cutter base; wherein the switcher and the stopper are attached to the switching plate so as to be movable together widthwise of the cutter base; wherein the switcher is provided on the outer surface side of the switching plate and is adapted to be switchable between a first position for causing the cutter lid to have a first opening angle and a second position for causing the cutter lid to have an second opening angle; and wherein the stopper is provided on the inner surface side of the switching plate and has a tilted surface, wherein, when the switcher is in the first position, opening the cutter lid allows an abutment provided at the cutter lid to engage the tilted surface of the stopper, whereby the opening angle of the cutter lid is held at the first angle, wherein, when the switcher is in the second position, the abutment and the tilted surface of the stopper disengage, so that the abutment butts against the switching plate and the opening angle of the cutter lid is held at the second angle. a cutter base having a fiber guide part for positioning the optical fiber; a slider, movably attached to the cutter base, having a blade member for incising the optical fiber; a cutter lid attached openably and closably to the cutter base; and an angle switching means for switching an opening angle of the cutter lid with respect to the cutter base, characterized in that the opening angle switching means has a switcher provided on the cutter base and a stopper adapted to operate in conjunction with the switcher so as to engage the cutter lid when the switcher is at a predetermined position; the opening angle switching means further has a switching plate arranged at a rear end part of the cutter base; wherein the switcher and the stopper are attached to the switching plate so as to be movable together widthwise of the cutter base; wherein the switcher is provided on the outer surface side of the switching plate and is adapted to be switchable between a first position for causing the cutter lid to have a first opening angle and a second position for causing the cutter lid to have an second opening angle; and wherein the stopper is provided on the inner surface side of the switching plate and has a tilted surface, wherein, when the switcher is in the first position, opening the cutter lid allows an abutment provided at the cutter lid to engage the tilted surface of the stopper, whereby the opening angle of the cutter lid is held at the first angle, wherein, when the switcher is in the second position, the abutment and the tilted surface of the stopper disengage, so that the abutment butts against the switching plate and the opening angle of the cutter lid is held at the second angle.