Abstract: The present invention is characterized in that an apparatus for bone fixation that is composed of a plate and screws fixing the plate to a bone, includes: screws that has a head portion having a male thread on the outer circumference while increasing in diameter toward the upper portion in a tapered shape; washers of which the outer circumference is formed convex, and which has, on the inner circumference, a slope that contact with the head portion such that the head portion of the screw is placed and a female thread that is engaged with the male thread of the head portion; and a plate that has locking holes which are bored concave in the up-down direction and have a holding step, where the washer is placed, on the inner circumference, in which when the washer and the head of which the female thread and the male thread are partially engaged are inserted from above the locking hole and placed on the holding step, as the head portion is moved down by thread-fastening, the washer is in close contact and fixed in