To provide a correction piece in straightening of a steel bar for reinforcement buried in lightweight foam concrete, capable of improving the adhesion between a rust preventive film and the steel bar for reinforcement by easily flawing the surface of the steel bar for reinforcement.

The correction piece straightening a steel bar for reinforcement buried in lightweight foam concrete is provided with a flawing part, in the straightening of a steel bar 10 for reinforcement coiled into a coil shape, abutted against the steel bar 10 for reinforcement to form a flaw on the surface of the steel bar 10 for reinforcement. In this way, even without performing a separate step for improving the adhesion with a fust preventive film to the steel bar 10 for reinforcement, in the straightening step of the ordinary production process of ordinary lightweight foam concrete, a flaw is formed on the surface of the steel bar 10 for reinforcement, and the adhesion between the rust preventive film and the steel bar 10 for reinforcement can be improved.