To provide a work presser for facilitating changing work for a broken tool and ensuring thrust of a plate as a work.

A work pressing bush 30 having a through-hole 47 in which the tool mounted on a spindle is inserted is previously fitted into a mounting groove 46 of a slender holder 31 and mounted therein in the state of being held in fixed attitude. A mounting base 32 is provided with a pair of detection holes 42a, 42b for tool breakage sensors 43a, 43b, facing each other with a mounting groove 40 held therebetween and the bush 30 is provided with detection passages 49a, 49b with a through-hole therebetween. When the holder 31 is detachably mounted in the mounting groove 40 of the forward/backward movable mounting base 32, the detection holes are communicated linearly with the detection passages.