To provide a method of manufacturing lightweight cellular concrete (ALC) capable of improving adhesion of rust-proof coatings to reinforcing bars by defining reduction of an area of the reinforcing bars embedded in the lightweight cellular concrete.

In the method for manufacturing the lightweight cellular concrete for embedding the reinforcing bars 10 for reinforcement which have undergone wire drawing, by using the reinforcing bars 10 for reinforcement in which reduction of the area in the wire drawing is defined as 5-15%, an ALC panel 1 is manufactured, so as to improve the adhesion of the rust-proof coatings to the reinforcing bars 10.