Bryocamptus (Echinocamptus) cheongokensis sp. nov. is a harpacticoid copepod of the family Canthocamptidae that was collected from a pool in Cheongok cave, Donghae-shi, Kangwon-do, Korea. The new species is characterized by the following diagnostic characters: 1) an eight-segmented female antennule, 2) the absence of an inner seta on the second exopodal segment of P1, 3) the distal segments of the exopod of P2 to P4 are as long as the other two segments combined, and 4) there are six setae on the basoendopod of the female P5. This species has a slight resemblance to the “hiemalis” group. However, the new species is clearly distinguishable from the species in the “hiemalis” group by the combination of ornamentation of the free margin of the operculum, the number of setae on the P4 endopod, the length/width ratio of the P5 exopod in the female, and the number of setae on the first endopod segment and the lengths of each apical seta on the last endopod segment of P3 in the male. Thus far, 22 species have been reported in the subgenus Echinocamptus, and the “hiemalis” group includes ten species. Species in this group are typically found in the interstitial groundwater around springs, lakes, streams, and caves. The new species described herein is the first described member of the subgenus Echinocamptus from caves in Korea.