A new species of the genus Halichondria (Eumastia) maraensis n. sp. (Demospongiae: Halichondrida: Halichondriidae) was collected from West Marado Island, Daejeong-eup, Seogwipo-si, Jeju-do Island, Korea during the period of Dec. 2006 to Feb. 2007 by a fishing net (60-80 m in depth). Halichondria (E.) maraensis n. sp. is similar to H. (E.) sitiens (Schmidt, 1870) in the type of the spicules. However they differ in spicules size and conical fistules at the surface. Oxeas of the new species are smaller and thicker than those of H. (E.) sitiens. Surface conules of the new species is not transparent, and has no oscules at the terminal short conules but H. (E.) sitiens has hollow papillae and terminal oscules.