The present invention relates to a medium composition containing an Ecklonia cava extract for dedifferentiation an induced pluripotent stem cell. Also, the present invention relates to a method for differentiating an induced pluripotent stem cell produced by using the medium composition into osteoblasts. When using the medium composition according to the present invention, induced pluripotent stem cells using mesenchymal stem cells can be produced efficiently, and the pluripotent stem cells which have been produced can be useful as a cell treatment agent by being capable of being differentiated into osteoblasts.
