A sealing device includes a seal member and a slinger. The slinger has a slinger fixing part, a first radial part, a first axial part, a second radial part, and a second axial part facing a seal fixing part of the seal member in a radial direction across a first clearance. The seal member has a large-diameter part facing, in an axial direction, an end of the second axial part on the other side in an axial direction across a second clearance. An outer circumferential surface of the large-diameter part and an outer circumferential surface of the second axial part are included in a flow passage surface of a continuous outside flow passage that extends in a straight line along the axial direction. The first clearance and the second clearance communicate with each other, and the sealing device has a labyrinth clearance including the first clearance and the second clearance.