The present invention relates to the novel use (anti-inflammatory activity) of Ramalin isolated from the Antarctic lichen Ramalina terebrata, and more specifically to a pharmaceutical composition containing Ramalin as an active ingredient. Ramalin of the invention is a compound derived from natural material, has no toxicity or side effects, and inhibits the expression of inducible nitric oxide synthase (iNOS) in the transcription stage to significantly inhibit the production of nitric oxide (NO) that is a key mediator of inflammatory responses. In addition, it inhibits the activation of the inflammatory mediator NF-κB, inhibits p38 MAPK, ERK1/2 and JNK signaling pathways, and inhibits the expression of the LPS receptor TLR4, suggesting that Ramalin has an excellent anti-inflammatory effect. Thus, the composition containing Ramalin can be effectively used to fundamentally treat or prevent inflammatory diseases or immune diseases and to relieve or alleviate the symptoms of the diseases.