A new marine sponge in the family Ancorinidae, Penares hongdoensis n. sp. was collected from Hongdo Island, Korea by SCUBA diving in 2004. P. hongdoensis n. sp. is closely related to P. cortius de Laubenfels, 1930 in their spicules. However, they differ in kind and size of spicules and growth form. The dichotriaene rhabds of new species are larger than that of P. cortius. And the new species has oxyaster, but P. cortius has oxyspheraster. Although the growth forms of both species are irregular massive, this new species shows conspicuous long projection toward upper part.