A stabilizer formed by using a metal bar having a solid structure and configured to reduce a displacement between right and left wheels, the stabilizer comprising a torsion part extending in a vehicle width direction, being capable of a torsional deformation, and having a diameter of 10 to 32 mm, wherein the stabilizer has a chemical composition containing at least C: 0.15% by mass or more to 0.39% by mass or less, Si: 0.05% or more to 0.40% or less, Mn: 0.50% or more to 1.70% or less, B: 0.0005% or more to 0.003% or less, Ni: 1.20% or less, Cr: 1.20% or less, Cu: 1.20% or less as essential elements, P: 0.040% or less and S: 0.040% or less, optionally comprising at least one or more elements selected from the group consisting of Mo, V, Ti, Nb, Al, N, Ca, and Pb each within a range of 1.20% or less as optional additive elements, and a balance of Fe and unavoidable impurities, and also has a metal structure 90% or more of which is a martensite structure, the stabilizer is quenched using water, the temperature of the water is 5 degrees C or more to 40 degrees C or less, after quenching, the stabilizer is not subjected to tempering, a compressive residual stress is present from the stabilizer surface to a depth of at least 0.8 mm, the compressive residual stress to the depth of 0.8 mm from the surface is 150 MPa or more under no load, and the stabilizer has a Rockwell hardness HRC of 44.5 or more, and a Charpy impact value of 30 J/cm2 or more at room temperature, wherein in the impact test, a Japanese industrial standard No. 3 piece, U notch 2 mm in depth, is sampled from the test material and used to determine the impact value uE20, a crossing point where the compressive residual stress changes over to a tensile residual stress is located deeper than a depth of 0.8 mm from the surface. a torsion part extending in a vehicle width direction, being capable of a torsional deformation, and having a diameter of 10 to 32 mm, wherein the stabilizer has a chemical composition containing at least C: 0.15% by mass or more to 0.39% by mass or less, Si: 0.05% or more to 0.40% or less, Mn: 0.50% or more to 1.70% or less, B: 0.0005% or more to 0.003% or less, Ni: 1.20% or less, Cr: 1.20% or less, Cu: 1.20% or less as essential elements, P: 0.040% or less and S: 0.040% or less, optionally comprising at least one or more elements selected from the group consisting of Mo, V, Ti, Nb, Al, N, Ca, and Pb each within a range of 1.20% or less as optional additive elements, and a balance of Fe and unavoidable impurities, and also has a metal structure 90% or more of which is a martensite structure, the stabilizer is quenched using water, the temperature of the water is 5 degrees C or more to 40 degrees C or less, after quenching, the stabilizer is not subjected to tempering, a compressive residual stress is present from the stabilizer surface to a depth of at least 0.8 mm, the compressive residual stress to the depth of 0.8 mm from the surface is 150 MPa or more under no load, and the stabilizer has a Rockwell hardness HRC of 44.5 or more, and a Charpy impact value of 30 J/cm2 or more at room temperature, wherein in the impact test, a Japanese industrial standard No. 3 piece, U notch 2 mm in depth, is sampled from the test material and used to determine the impact value uE20, a crossing point where the compressive residual stress changes over to a tensile residual stress is located deeper than a depth of 0.8 mm from the surface.