The case was a 29 year old female who has suffered from systemic lupus erythematosus (SLE) since 15 years of age. The activity of SLE was low, and she took prednisolone orally. Her first pregnancy failed after 14 weeks. In the second pregnancy, she had thrombocytopenia, prolonged activated partial thromboplastin time (APTT), positive lupus anticoagulant (LAC) and thus was diagnosed with antiphospholipid antibody syndrome (APS). Combination therapy with steroids and aspirin was started, and she underwent treatment of double filtration plasmapheresis (DFPP) in the early stage of pregnancy. Her platelet count increased, and the value of APTT has normalized with DFPP treatment. She delivered successfully on the 32nd week of pregnancy. We think that DFPP is an effective and safe treatment in patients with an LAC positive pregnancy.