Abstract: A device for fixing a work in position on a base having a protrusion and a hole formed adjacent the protrusion for mounting the device. The device includes a rotational member mountable in the hole of the base and rotatable around the axis of the hole. The rotational member has a shank insertable into the hole and a head disposed on an upper end of the shank. The head is provided with a lateral surface for pressing the work against the protrusion. The distance from the rotational axis of the rotational member to the lateral surface is varied in a circumferential direction of the head. The rotational member further includes a first engaging portion for engagement with a tool for rotating the rotational member. A threaded hole is formed to extend from the head to the shank along the rotational axis of the rotational member. A screw member is threadably engaged with the threaded hole of the rotational member and has a second engaging portion for engagement with another tool for rotating the screw member.