A cut-off machine comprising: a rotary shaft; a blade having a circular shape, and having, in a central portion thereof, an insertion hole in which the rotary shaft is inserted; a holding mechanism configured to hold the blade with respect to the rotary shaft, and including a pair of holding members (31, 32) which each has an annular shape and which clamp the blade therebetween; a fixed guard configured to cover a portion of an outer periphery of the blade, and including a fixed support which is provided with a bearing portion rotatably supporting the rotary shaft; a movable guard configured to movably cover a portion of the outer periphery of the blade, the portion being circumferentially adjacent to the portion covered with the fixed guard, the movable guard having a movable base formed to surround a periphery of the rotary shaft; and a coupling mechanism configured to couple the movable guard to the fixed guard such that the movable guard can be turned around the rotary shaft, and including a first coupling member, a second coupling member, characterized in that the coupling mechanism further includes coupling bolt, the first coupling member being disposed between the fixed support and the movable base, the second coupling member being disposed between the movable base and the pair of holding members (31, 32), the first coupling member and the second coupling member slidably clamping the movable base therebetween, the coupling bolt fixing the first coupling member to the fixed support, wherein an inner peripheral edge of the movable base is located closer to the rotary shaft than the coupling bolt is, the movable base is provided with a slot having an arc shape extending in a circumferential direction of the rotary shaft, the first coupling member is provided with a first insertion hole communicating with the slot, the second coupling member is provided with a second insertion hole communicating with the slot, and the coupling bolt is sequentially inserted into the second insertion hole, the slot, and the first insertion hole, and is screwed into the fixed support. a rotary shaft; a blade having a circular shape, and having, in a central portion thereof, an insertion hole in which the rotary shaft is inserted; a holding mechanism configured to hold the blade with respect to the rotary shaft, and including a pair of holding members (31, 32) which each has an annular shape and which clamp the blade therebetween; a fixed guard configured to cover a portion of an outer periphery of the blade, and including a fixed support which is provided with a bearing portion rotatably supporting the rotary shaft; a movable guard configured to movably cover a portion of the outer periphery of the blade, the portion being circumferentially adjacent to the portion covered with the fixed guard, the movable guard having a movable base formed to surround a periphery of the rotary shaft; and a coupling mechanism configured to couple the movable guard to the fixed guard such that the movable guard can be turned around the rotary shaft, and including a first coupling member, a second coupling member, characterized in that the coupling mechanism further includes coupling bolt, the first coupling member being disposed between the fixed support and the movable base, the second coupling member being disposed between the movable base and the pair of holding members (31, 32), the first coupling member and the second coupling member slidably clamping the movable base therebetween, the coupling bolt fixing the first coupling member to the fixed support, wherein an inner peripheral edge of the movable base is located closer to the rotary shaft than the coupling bolt is, the movable base is provided with a slot having an arc shape extending in a circumferential direction of the rotary shaft, the first coupling member is provided with a first insertion hole communicating with the slot, the second coupling member is provided with a second insertion hole communicating with the slot, and the coupling bolt is sequentially inserted into the second insertion hole, the slot, and the first insertion hole, and is screwed into the fixed support.