A 66-year-old woman presented with exertional dyspnea and productive cough. Chest radiography showed ground glass opacities and patchy infiltrates in both lungs. After confirmation of pulmonary alveolar proteinosis by bronchoalveolar lavage, she underwent conventional whole-lung lavage with slight improvement, with the aid of a partial extracorporeal circulation. After aggravation for one year, a modified lavage technique using high-frequency jet ventilation was used, and persistent improvement in oxygenation was achieved. We believe that this modified technique could be a useful method for pulmonary alveolar proteinosis.