Herein, we propose a piecewise-linear particle swarm optimizer (PPSO).PPSO is one of the deterministic PSO, which has two search dynamics, a convergence mode and a divergence mode.Solving performances of PPSO are significantly affected by connective coefficient &#947.We investigate relations between solving performances and the connective coefficient, and reveal a method of setting the connective coefficient according to the structure of a solution space.We further compare the solving performances of PPSO with those of other deterministic PSO methods and classic PSO in the numerical experiments.