In this research, several design methods of FIR (Finite Impulse Response) filters with CSD (Canonic Signed Digit) coefficient are compared to investigate a search process of each method. The design problem is formulated as a 1, 0, −1 combinatorial optimization problem. In this problem, high computation time is required to obtain the optimal solution. Thus, many design methods using metaheuristic approaches have been proposed. In this study, the search process of design methods is verified. As a result, the differences between the design methods are clarified and thus it is expected that some cues for improving the performance can be attained.