A sealing device which allows the man-hour for mounting the sealing device to be reduced is provided. A sealing device includes: a slinger fitted and fixed to an end portion of an inner shaft; a core metal fitted and fixed to an end portion of an outer ring; an inner seal lip fixed to the core metal and in slidable contact with the slinger; an outer seal lip fixed to the core metal radially outward of the inner seal lip and in slidable contact with a side surface of a flange portion; and a labyrinth lip fixed to the core metal radially outward of the outer seal lip and forming a labyrinth seal together with the side surface of the flange portion.