The present invention relates to a novel Pediococcus genus microorganism and more particularly, Pediococcus pentosaceus EROM101 (KCCM-10517) originated from human intestines having immune enhancement, anticancer and antiviral activities and a use thereof. Due to its excellent immune enhancement, anticancer and antimicrobial activities by activating macrophages/spleen cells and inducing gut immunity, the Pediococcus pentosaceus EROM101 of the present invention can be effectively used for the production of various products such as immune enhancement agent, anticancer agent, antimicrobial agent, food additive, intestinal function-controlling agent, live bacterial agent, feed additive and other fermented products.