An optical fiber cleaver comprising: a body unit on which an optical fiber extending in a first direction is loaded; a lid unit that connected to the body unit to be rotatable and configured to be openable with respect to the body unit; a pair of retainers (20, 22) arranged in the body unit to be separate from each other in the first direction and retain the optical fiber between the pair of retainers (20, 22) when the lid unit is closed with respect to the body unit; a blade member arranged in the lid unit and configured to come into contact with the optical fiber from one direction side of a second direction intersecting the first direction between the pair of retainers (20, 22) and hurt the optical fiber; a movement unit) arranged in the lid unit and configured as a movement unit moving the blade member and configured to bring the blade member into contact with the optical fiber from the one direction side of the second direction and move the blade member to one direction side of a third direction intersecting the first and second directions; and a cleaving mechanism arranged in the body unit configured to advance the hurt of the optical fiber and cleave the optical fiber; characterized in that the movement unit is provided to be movable with respect one of the body unit and the lid unit, wherein at least one alignment groove (60, 60A) is formed in a first surface of one of the movement unit and one of the body unit and the lid unit, the first surface including the second and third directions, wherein at least one protrusion which is able to engage with at least the one alignment groove (60, 60A) is provided in a second surface of the other of the movement unit and the one of the body unit and the lid unit, the second surface including the second direction and the third direction, and wherein the movement unit is movable to the other direction side of the second direction along a shape of at least the one alignment groove (60, 60A) and is subsequently movable to the one direction side of the third direction in accordance with a user operation. a body unit on which an optical fiber extending in a first direction is loaded; a lid unit that connected to the body unit to be rotatable and configured to be openable with respect to the body unit; a pair of retainers (20, 22) arranged in the body unit to be separate from each other in the first direction and retain the optical fiber between the pair of retainers (20, 22) when the lid unit is closed with respect to the body unit; a blade member arranged in the lid unit and configured to come into contact with the optical fiber from one direction side of a second direction intersecting the first direction between the pair of retainers (20, 22) and hurt the optical fiber; a movement unit) arranged in the lid unit and configured as a movement unit moving the blade member and configured to bring the blade member into contact with the optical fiber from the one direction side of the second direction and move the blade member to one direction side of a third direction intersecting the first and second directions; and a cleaving mechanism arranged in the body unit configured to advance the hurt of the optical fiber and cleave the optical fiber; characterized in that the movement unit is provided to be movable with respect one of the body unit and the lid unit, wherein at least one alignment groove (60, 60A) is formed in a first surface of one of the movement unit and one of the body unit and the lid unit, the first surface including the second and third directions, wherein at least one protrusion which is able to engage with at least the one alignment groove (60, 60A) is provided in a second surface of the other of the movement unit and the one of the body unit and the lid unit, the second surface including the second direction and the third direction, and wherein the movement unit is movable to the other direction side of the second direction along a shape of at least the one alignment groove (60, 60A) and is subsequently movable to the one direction side of the third direction in accordance with a user operation.