A stabilizer for a vehicle, comprising: a torsion portion suspended from a vehicle body via a cylindrical bush; a pair of arm portions (3, 4) extending from ends (2L, 2R) of the torsion portion to right and left wheels, and attached to a suspension units; and a restriction ring coupled to the torsion portion at a site adjacent to the bush, wherein the restriction ring includes: a main body formed in a strip shape; a female portion including a valley bottom portion located at the other end of the main body, and a pair of sandwiching portions (32, 33) spaced apart from each other by an interval in an axial direction of the torsion portion with the interval being narrow at a position farther from the valley bottom portion; a male portion including a neck portion extending from an end of the main body and inserted between distal ends of the pair of sandwiching portions, an expanding portion being larger in the axial direction of the torsion portion at a position farther from the neck portion, and a contracting portion being smaller in the axial direction of the torsion portion at a position farther from the neck portion; and a weld portion where the male portion and the female portion are welded, and the weld portion covers at least a range of the contracting portion and the valley bottom portion as viewed from an outer peripheral surface of the restriction ring, and melts in a thickness direction from the outer peripheral surface to integrate the contracting portion and the valley bottom portion, characterized in that the restriction ring further includes a surrounding portion surrounding the weld portion tc expose the outer peripheral surface from the weld portion, the surrounding portion includes a female side surrounding portion formed integrally with the female portion and a male side surrounding portion formed integrally with the male portion, and the female side surrounding portion and the male side surrounding portion are formed to be flush with each other in the axial direction of the torsion portion. a torsion portion suspended from a vehicle body via a cylindrical bush; a pair of arm portions (3, 4) extending from ends (2L, 2R) of the torsion portion to right and left wheels, and attached to a suspension units; and a restriction ring coupled to the torsion portion at a site adjacent to the bush, wherein the restriction ring includes: a main body formed in a strip shape; a female portion including a valley bottom portion located at the other end of the main body, and a pair of sandwiching portions (32, 33) spaced apart from each other by an interval in an axial direction of the torsion portion with the interval being narrow at a position farther from the valley bottom portion; a male portion including a neck portion extending from an end of the main body and inserted between distal ends of the pair of sandwiching portions, an expanding portion being larger in the axial direction of the torsion portion at a position farther from the neck portion, and a contracting portion being smaller in the axial direction of the torsion portion at a position farther from the neck portion; and a weld portion where the male portion and the female portion are welded, and the weld portion covers at least a range of the contracting portion and the valley bottom portion as viewed from an outer peripheral surface of the restriction ring, and melts in a thickness direction from the outer peripheral surface to integrate the contracting portion and the valley bottom portion, characterized in that the restriction ring further includes a surrounding portion surrounding the weld portion tc expose the outer peripheral surface from the weld portion, the surrounding portion includes a female side surrounding portion formed integrally with the female portion and a male side surrounding portion formed integrally with the male portion, and the female side surrounding portion and the male side surrounding portion are formed to be flush with each other in the axial direction of the torsion portion. a main body formed in a strip shape; a female portion including a valley bottom portion located at the other end of the main body, and a pair of sandwiching portions (32, 33) spaced apart from each other by an interval in an axial direction of the torsion portion with the interval being narrow at a position farther from the valley bottom portion; a male portion including a neck portion extending from an end of the main body and inserted between distal ends of the pair of sandwiching portions, an expanding portion being larger in the axial direction of the torsion portion at a position farther from the neck portion, and a contracting portion being smaller in the axial direction of the torsion portion at a position farther from the neck portion; and a weld portion where the male portion and the female portion are welded, and the weld portion covers at least a range of the contracting portion and the valley bottom portion as viewed from an outer peripheral surface of the restriction ring, and melts in a thickness direction from the outer peripheral surface to integrate the contracting portion and the valley bottom portion, characterized in that the restriction ring further includes a surrounding portion surrounding the weld portion tc expose the outer peripheral surface from the weld portion, the surrounding portion includes a female side surrounding portion formed integrally with the female portion and a male side surrounding portion formed integrally with the male portion, and the female side surrounding portion and the male side surrounding portion are formed to be flush with each other in the axial direction of the torsion portion.