NOVELTY - Creating particle size distribution model that simulates particle size distribution of cluster of particles of catalyst metal of fuel cell comprises determining particle size range of cluster of particles of catalyst metal to be simulated; integrating frequency of appearance; dividing integration region into given number of regions; obtaining particle size distribution model by assuming particle size distribution containing particles having particle sizes, where particle size distribution is plotted such that frequency of appearance of particles is equal to integral obtained for each regions.    USE - Method is used for creating particle size distribution model that simulates particle size distribution of cluster of particles of catalyst metal of fuel cell.    ADVANTAGE - The method predicts degradation of catalyst metal of fuel cell, and controls fuel cell.    DETAILED DESCRIPTION - Creating particle size distribution model that simulates particle size distribution of cluster of particles of catalyst metal of fuel cell comprises:    (A) determining particle size range by determining minimum particle size and maximum particle size of cluster of particles of catalyst metal to be simulated;    (B) integrating frequency of appearance of particles in determined particle size range, over integration region defined by minimum particle size as starting point and maximum particle size as an endpoint;    (C) dividing integration region into given number of regions through first dividing operation, using integral of frequency of appearance, so that integrals obtained for individual regions into which the integration region is divided are substantially equal, and determining particles sizes, of division points at which integration region is divided;    (D) determining minimum particle size, maximum particle size and particle sizes of the respective division points, as typical points; and    (E) obtaining particle size distribution model by assuming particle size distribution containing particles having particle sizes of respective typical points, where particle size distribution is plotted such that frequency of appearance of particles having particle size of each of typical points is equal to integral obtained for each of regions into which integration region is divided at typical points.