[Purpose] This study investigated the effects of supine position maintained by a stretch pole and deep breathing exercise on pulmonary function. [Methods] Thirty-six young healthy participants were randomly divided into three groups: the group maintaining the supine position on a stretch pole (SP group), the group doing deep breathing using an incentive spirometer (DB group), and the no intervention group. The participants in the two intervention groups participated in ten sessions for two weeks. Pulmonary function was evaluated by vital capacity (VC), %VC, forced vital capacity (FVC), forced expiratory volume in one second (FEV1)，and FEV1/FVC. The data was analyzed using a repeated measures split-plot analysis of variance, multiple comparison test, and paired t-test. [Results] After the intervention, the VC and FVC for the SP group significantly increased whereas FEV 1 and FEV1/FVC for the DB group significantly decreased. The amounts of the changes in VC and FVC were significantly larger in the SP group than the nointervention group, and the amounts of the changes in FVC and FEV1 were significantly larger in the SP group than the DB group. [Conclusion] The results suggest that the supine position maintained a stretch pole may be helpful to improve the lung volume in young heathy people.