In this study, we conducted antioxidant and whitening experiments to find out the functionality of Dictyopteris pacifica, Dictyopteris prolifera and Dictyopteris divaricata extracts of Dictyopteris spp. of brown algae as cosmetic ingredients. For the experiment, the extracts of D. pacifica, D. prolifera and D. divaricata were prepared with 70% ethanol. In the antioxidant experiment, the measurement result of total phenolic contents showed that the D. divaricata extract was the highest, 301.25±1.38 mg gallic acid/g. In the DPPH radical scavenging activity, the D. divaricata extract was also the highest, 99.40±0.16%. Also in the ABTS radical scavenging activity experiment, the D. divaricata extract was high, 98.87±0.62% results. In the NO radical scavenging activity, the D. divaricata extract was also the highest, 76.80±1.27%. The measurement result of tyrosinase inhibition activity in the whitening experiment showed that the D. prolifera extract was high, 43.5±1.5%. In the cytotoxicity experiment, all three types of Dictyopteris spp. extracts showed the high cell viability of more than 80%. In the measurement of melanin contents using B16F10 melanoma cells, the D. pacifica extract showed the best result, 33.90±1.70%. Thus, it was found that the antioxidant effect was high in the D. divaricata extract, and the whitening effect was high in D. prolifera and D. pacifica extracts, respectively. Therefore, the purpose of this study is to present the Dictyopteris spp. extract as basic data necessary to use it as a functional cosmetic ingredient with natural antioxidant and whitening effects in the future.