A tool to evaluate the subjective wearing comfort of baseball caps from the objective measurement of pressure was developed. Comfortable fit-ability index (CFI) and holding power were defined to represent the subjective wearing comfort of caps. As a preliminary step to define the CFI, average pressure, pressure distribution and standard deviation of pressure were obtained and subjective sensation were evaluated by wearing caps. The holding power was also estimated from wind tunnel testing. Two sets of baseball caps were evaluated, one set made of elastic fabric (F-caps) and the other set made of non- elastic fabric (S-caps). F-caps began to be taken off by the higher wind velocity and thus exhibited higher values of holding power. On the other hand, F-caps exerted lower average pressure, a narrower pressure distribution, and smaller standard deviation. It was concluded that caps employing elastic fabric were more comfortable since their pressure was rather evenly distributed and still maintaining higher holding power.