A method of plasma particle simulation capable of preventing solution divergence. A space within a housing chamber of a plasma processing apparatus is divided into a plurality of cells. A weighting factor corresponding to the number of plasma particles represented by a superparticle is set in each of the divided cells. Superparticles are set in each of the divided cells using plasma particles contained in the divided cell and the set weighting factor. The behavior of the superparticles in each of the divided cells is calculated. The weighting factor becomes smaller as the divided cell is located closer to a solid wall surface of the housing chamber.