PROBLEM TO BE SOLVED: To provide an implant which is capable of maintaining a high fixing force to a bone in a period up to the healing of the bone, and being cleared off after the healing of the bone.SOLUTION: An implant 1 comprises: a screw body 3 made from pure magnesium or a magnesium alloy and having a male thread 2； and an anodic oxide coating 4 covering the outer surface of the screw body 3. The male screw 2 has a clearance flank 21 that faces forward in the movement direction during screwing in of the screw body 3, and a pressure flank 22 that faces rearward in the movement direction. The biodegradation period of the anodic oxide coating 41 on the clearance flank 21 is shorter than the biodegradation period of the anodic oxide coating 42 on the pressure flank 22.【課題】骨治癒までの期間は骨に対する高い固定力を維持しながらも、骨治癒の後は速やかに消滅する。【解決手段】純マグネシウムまたはマグネシウム合金からなり、雄ねじ２を有するねじ本体３と、該ねじ本体３の外表面を被覆する陽極酸化皮膜４とを備え、雄ねじ２が、ねじ本体３のねじ込み時に進行方向前方を向く遊び側フランク２１と、進行方向後方を向く圧力側フランク２２とを有し、遊び側フランク２１上の陽極酸化皮膜４１の生分解期間が、圧力側フランク２２上の陽極酸化皮膜４２の生分解期間よりも短いインプラント１を提供する。【選択図】図１
