From an examination of caprellid specimens collected from Korea, we found a new species belonging to the genus Perotripus. This new species is clearly distinguished from two previously recorded species, P. brevis and P. keablei, in having an acute projection and blunt apex of distal segment of pereopod 5. This genus Perotripus is reported from Korea for the first time. We described it with figures in detail. As a result, Korean caprellid fauna consists of 35 species in seven genera.