A 75-year-old woman with Sjögren's syndrome was referred to our hospital because of an abnormal chest radiograph. A bronchofiberscopic examination revealed diffuse alveolar hemorrhage. We treated it as antineutrophil cytoplasmic antibody (ANCA)-related diffuse alveolar hemorrhage because of positive myeloperoxidase (MPO)-ANCA. Blood sputum disappeared when combination therapy of corticosteroid and cyclophosphamide was performed. However, the D-dimer value was high, and the estimated pulmonary artery pressure was increased. On a contrast-enhanced CT examination, a left pulmonary artery thrombus was observed. Anticardiolipin antibody was confirmed to be positive, and the patient was diagnosed with antiphospholipid antibody syndrome. No reports of a simultaneous occurrence of ANCA-related alveolar hemorrhage or antiphospholipid antibody syndrome follow-up with Sjögren's syndrome have been made.