<p>A sealing device adapted to seal an outer periphery of a shaft member inserted into a tubular member includes a dust seal lip arranged on an outer side of the tubular member and an oil seal lip arranged on an inner side of the tubular member to form a space for accumulating working fluid between the oil seal lip and the dust seal lip. The dust seal lip includes a main lip portion and an auxiliary lip portion formed to be closer to the oil seal lip than the main lip portion. A maximum value of a surface pressure gradient absolute value of the inner side in the auxiliary lip portion is set to be larger than that of a surface pressure gradient absolute value of the outer side in the auxiliary lip portion.</p>
