We report the case of a 71-year-old man with rheumatoid arthritis. Infliximab administration was started as treatment for rheumatoid arthritis in January 2009. As he showed a positive result for the tuberculin test, he was treated with isoniazid for 9 months. He was subsequently referred to our department in October 2011 with a right-sided pleural effusion. When thoracoscopy was performed under local anesthesia, white and red protruding lesions of various sizes were observed in the pleural cavity. A biopsy revealed fibrous granulation tissue, and tissue culture and all sensitivity tests were positive for Mycobacterium tuberculosis. Therefore, thoracoscopy is useful for not only diagnosis but also determining whether resistant tuberculosis is present.