Abstract: The peptides according to the present invention have a high surfactant activity, but no or little hemolytic activity and comprises D-amino acid and acids at a rate of approximately 5% to 40% of the structuring amino acids. The pulmonary surfactant composition of the present invention comprises a mixture of the peptide with a natural lecithin such as soy lecithin and so on Therefore, the pulmonary surfactant composition can be expected to be developed as a pulmonary surfactant without using any animal-derived substance, which has a high surfactant activity and can be produced at reasonable costs and on a large scale.