The measuring tests on the rest position capacity and the tongue volume were conducted on the one hundred normal dental college students and staffs of Seoul National University in order to study the relationships between the est position Capacity and tongue volume. The results were as follows : 1) The correlation between the rest position capacity and tongue volume was hardly recognized. 2) The correlation between tongue volume and the weight was recognized. 3) Physiologic reflex was coused by the water injected in the mouth in the rest position. 4) Each correlation of the height and cheek thickness to the tongue volume was not recognized.