Rice blast is one of the most devastating diseases, particularly panicle blast leads to significant yield losses. Utilization of panicle blast resistance genes is one of the effective ways to control this disease. However, genetic resources with panicle blast resistance are rare. The objective of this study was to identify the role of OsEXOIII-1, a previously identified candidate gene, in Pigm-mediated panicle blast resistance in rice. There were two main haplotypes in rice germplasm, with OsEXOIII-1^Hap1, the product of the resistant haplotype, binding more strongly to PiBP1 than OsEXOIII-1^Hap2. OsEXOIII-1/PiBP1 positively regulates Pigm-mediated panicle blast resistance by regulating expression of PR1 subfamily genes. OsEXOIII could be a target for breeding panicle blast-resistant cultivars.