In this research, a chemical roughening method was proposed as a new surface treatment technique for making a roughened surface of existing concrete. In this new method, the concrete surface is deteriorated with acid to make a roughened surface. Acids suitable for chemical roughening method were investigated using various acids. As a result, acetic acid was selected as the optimum acid. The bond strength of the roughened surface obtained by this roughening method satisfied the specified value of the NEXCO standard. The effectiveness of the proposed chemical roughening method was confirmed by this research.