To provide a crawler belt seal device which enhances seal durability against load applied in a compression direction and stabilizes seal performance satisfactorily for a long time and seal to be used for the device.

This crawler belt seal device is characterized in that it is provided with seal comprising a first annular seal body 32 having an H-shaped cross section, a second annular seal body 34 forming a relative sliding seal surface between a fist annular side piece part 29 consisting of the first annular seal body 32 and the side surface of an annular space, and between a second annular side piece part 30 and an end surface of the bush 23, respectively, and a third annular seal body 35.