In this study, we intended to report a case of Dibothriocephalus nihonkaiensis infection diagnosed in Suzu City, Ishikawa Prefecture, Japan. A 23-year-old man from Aichi Prefecture moved to Suzu City, one of the most severely destroyed areas by the 2024 Noto Peninsula earthquake, to engage in reconstructive works. He visited the internal medicine department of Suzu General Hospital by the passage of long slender worm in his stool. Numerous operculated helminth eggs were detected from his stool samples, and a tapeworm strobila with the scolex was found after the treatment of praziquantel (10 mg/kg). Magnesium citrate was administered before and after praziquantel treatment, and stool samples were collected from the patient. The expelled tapeworm measured approximately 1.7 m in length. Morphological examination revealed a relatively small scolex with 2 suckling grooves, suggesting an immature adult specimen. Phylogenetic analysis of the mitochondrial 16S rRNA and cox1 genes identified the parasite as Dibothriocephalus nihonkaiensis. This case highlights the importance of integrating morphological and molecular approaches for accurate species identification in cases with complex epidemiological backgrounds.