A 56-year-old woman presented with complaints of general malaise and left chest pain. Chest radiography and CT scanning revealed multiple nodules and infiltrations in both lung fields. Her symptoms diminished and the extent of some of the lung shadows decreased spontaneously. However, since new shadows appeared later in other parts of the lung, she was admitted to our hospital on September 3. A transbronchial lung biopsy was not adequate for diagnosing a particular disease. But thoracoscopic lung biopsy specimens revealed necrosis with localized pleural fibrosis, and so a diagnosis of pulmonary infarction was made. The patient did not have any underlying disease or coagulation abnormalities, but Sjögren's syndrome and an antipsychotic agent were suspected to be background factors.