A 75-year-old Japanese man underwent thoracic surgery to treat a large lung cancer lesion in the left upper lobe with calcified pleural thickening. Postoperatively, viable Mycobacterium tuberculosis was detected in the margin of the resected thickened calcified pleural lesion. Therefore, an infection control investigation of medical staff who had come in contact with the patient was conducted. Consequently, two of the 14 healthcare professionals who had been in the operating room were diagnosed with latent tuberculous infections. Therefore, strict precautions against airborne infections are required to prevent the in-hospital transmission of M. tuberculosis in such cases.