The medical handpiece of the present invention includes a cutting tool having a flexible shank and a cutting bur, a plastically deformable tubular casing for the cutting tool, a handpiece body detachably holding the cutting tool, bearing members disposed in the casing, an inner intervening member for receiving the shank, and an outer intervening member arranged around the inner intervening member. The inner and outer intervening members are composed of a plurality of segments, and each segment is arranged between or on distal or proximal side of the bearing members. Each segment of the outer intervening member is further composed of a plurality of sub-segments. Annular members having the outer diameter that is larger than that of the outer intervening member are arranged between the sub-segments of the outer intervening member. The present handpiece provides improved operationality since shaking is hardly generated even when the casing is flexed.