A 68-year-old female who had Raynaud phenomenon for a decade was admitted to our hospital in January 2012. She complained of sclerodactyly and scleroderma that did not extend past the elbows. She also had fingertip ulcers that repeatedly disappeared and recurred for several years. Blood tests showed that she was anti-centromere antibody positive. Therefore, she was diagnosed with limited cutaneous systemic sclerosis. Two months after diagnosis, she returned to our hospital because she experienced dyspnea on exertion and exacerbation of her fingertip ulcers. Chest X-rays revealed cardiac enlargement, an echocardiography showed tricuspid regurgitation with an increased tricuspid pressure gradient (91 mmHg) and right heart catheterization showed a mean pulmonary arterial pressure of 59 mmHg. Chest computed tomography and lung perfusion scintigraphy showed no abnormalities. She was then diagnosed with pulmonary arterial hypertension associated with systemic sclerosis. She improved rapidly with daily treatments of prednisolone in addition to warfarin, bosentan and beraprost sodium. This is a rare case of rapidly progressive pulmonary arterial hypertension associated with systemic sclerosis that can be markedly improved with early diagnosis and treatment.