A sealing structure (1, 5) for sealing a space between a shaft extending in an axis direction and a rotational body in which a through-hole extending in the axis direction is formed and the shaft is inserted through the through-hole with a space, the sealing structure (1, 5) characterized in comprising: a sealing device attached to one of the shaft and the rotational body in a relatively irrotational manner; a contacted portion formed in another of the shaft and the rotational body in a relatively irrotational manner, wherein the sealing device includes an inner side seal portion, an outer side seal portion, and a dust cover (13, 60), the contacted portion includes a peripheral surface in an annular shape centered about the axis, the inner side seal portion includes an inner side attachment ring having an annular shape centered about the axis and attached to the one of the shaft and the rotational body in a relatively irrotational manner, and an inner side seal lip formed of an elastic body having an annular shape centered about the axis and attached to the inner side attachment ring, and the inner side seal lip extends from the inner side attachment ring toward an outer side that is a side toward which one direction along the axis direction faces, and slidably abuts the contacted portion at a part on the outer side, the outer side seal portion includes an outer side attachment ring having an annular shape centered about the axis and fitted to the inner side attachment ring of the inner side seal portion, an outer side seal lip formed of an elastic body having an annular shape centered about the axis and attached to the outer side attachment ring, and a side lip formed of an elastic body having an annular shape centered about the axis and attached to the outer side attachment ring on a side separate from the contacted portion than the outer side seal lip, the outer side seal lip extends from the outer side attachment ring toward the outer side, and slidably abuts the dust cover (13, 60) at a part on the outer side, and the side lip slidably abuts the dust cover (13, 60) at an end portion on the outer side, a gap being formed between the dust cover (13, 60) and a member to which the inner side attachment ring is attached, characterised in that the outer side seal lip is positioned on the outer side of the inner side seal lip, the side lip extends from the outer side attachment ring toward the outer side, and the dust cover (13, 60) is an annular member attached to a peripheral surface of the contacted portion. a sealing device attached to one of the shaft and the rotational body in a relatively irrotational manner; a contacted portion formed in another of the shaft and the rotational body in a relatively irrotational manner, wherein the sealing device includes an inner side seal portion, an outer side seal portion, and a dust cover (13, 60), the contacted portion includes a peripheral surface in an annular shape centered about the axis, the inner side seal portion includes an inner side attachment ring having an annular shape centered about the axis and attached to the one of the shaft and the rotational body in a relatively irrotational manner, and an inner side seal lip formed of an elastic body having an annular shape centered about the axis and attached to the inner side attachment ring, and the inner side seal lip extends from the inner side attachment ring toward an outer side that is a side toward which one direction along the axis direction faces, and slidably abuts the contacted portion at a part on the outer side, the outer side seal portion includes an outer side attachment ring having an annular shape centered about the axis and fitted to the inner side attachment ring of the inner side seal portion, an outer side seal lip formed of an elastic body having an annular shape centered about the axis and attached to the outer side attachment ring, and a side lip formed of an elastic body having an annular shape centered about the axis and attached to the outer side attachment ring on a side separate from the contacted portion than the outer side seal lip, the outer side seal lip extends from the outer side attachment ring toward the outer side, and slidably abuts the dust cover (13, 60) at a part on the outer side, and the side lip slidably abuts the dust cover (13, 60) at an end portion on the outer side, a gap being formed between the dust cover (13, 60) and a member to which the inner side attachment ring is attached, characterised in that the outer side seal lip is positioned on the outer side of the inner side seal lip, the side lip extends from the outer side attachment ring toward the outer side, and the dust cover (13, 60) is an annular member attached to a peripheral surface of the contacted portion.