A 47-year-old woman had undergone a previous medical examination for her chief complaint of cough with bloody sputum, which had continued for one month. Because chest computed tomography identified nodular opacity of the left lung hilar region, she was admitted to our hospital. Although she revealed an accumulation of FDG-PET (SUVmax 3.1) in the nodular opacity of the left lung hilar region, we could not reach a confirmed diagnosis and the opacity disappeared naturally. Because left pleural effusion appeared 3 months later, we performed thoracoscopic pleural biopsy and the histopathological examination revealed the bug eggs of Paragonimus westermani. After the definitive diagnosis, praziquantel was administered, there was a decrease in left pleural effusion and there has been no recurrence in 2 years follow-up. Cases of Paragonimus westermani diagnosed by thoracoscopic pleural biopsy are very rare.