We encountered a 54-year-old Japanese man who presented with painless swellings on his bilateral neck. Although ultrasonographic findings suggested metastatic lymphadenopathy, histological examination of the mass revealed non-caseous granulation lymphadenitis. He was subsequently diagnosed as having prostate carcinoma with metastasis to the multiple bones. The present case suggested that prostate carcinoma could cause cervical lymphadenopathy due to non-caseous granulation as an initial manifestation, and could be a sign for an impending clinical expression of metastasis to an area draining to the lymph nodes.