Marine organism extracts were prepared from 26 species of Korean indigenous marine organisms, including 25 species belonging in class Anthozoa of phylum Cnidaria and a species belonging to subphylum Urochordata of phylum Chordata, and screened their inhibitory effects against ${mu}$-calpain. As a result, the thirteen extracts were found to be active in the criteria of $IC_{50}$ < 100 ${mu}g/ml$. Among them, the MeOH extracts of Plexauroides praelonga and Alveopora japonica showed remarkable ${mu}$-calpain inhibitory activity with $IC_{50}$ values of $4.62{pm}0.22$ and $4.82{pm}0.07{mu}g/ml$, respectively. In addition, chemical investigation of A. japonica led to the isolation of an active compound, hexadecyl tetradecanoate, as a selective cathepsin B inhibitor ($IC_{50}=9.05{pm}2.45{mu}M$). This compound was isolated as constituent of A. japonica for the first time in the present study.