This paper proposes a computational form-finding method for integrating parametric origami design and acoustic engineering to find the best geometric form of a concert hall. The paper describes an application of this method to a concert hall design project in Japan. The method consists of three interactive subprograms: a parametric origami program, an acoustic simulation program, and an optimization program. The advantages of the proposed method are as follows. First, it is easy to visualize engineering results obtained from the acoustic simulation program. Second, it can deal with acoustic parameters as one of the primary design materials as well as origami parameters and design intentions. Third, it provides a final optimized geometric form satisfying both architectural design and acoustic conditions. The method is valuable for generating new possibilities of architectural form by shifting from a traditional form-making process to a form-finding process.