Eight strains of Trichaptun (Polyporaceae), two strains from each species of T. abietinum, T. biforme, T. fusco-violaceum, and T. laricinum were examined to see their phylogenetic relationship by digesting mitochondrial DNAs with EcoRV, Hind III, XbaI, and PstI, and then analyzing fragmentation patterns with the methods of Nei and Li. T. abietinum, T. biforme, and T. laricinum developed an independent phylogenetic lineage, respectively, but T. fusco-violaceum FP-133997-sp showed a close relationship with two strains of T. bioforme, and T. fusco-violaceum HHB-4016-sp barely grouped with those of T. laricinum. Based on the results of the RFLP analysis of mtDNA, it is concluded that T. fusco-violaceum is under way to differentiation into two different subgroups.