A crawler belt (6) has engaging recessed portions (62) on an inner circumferential surface of the crawler belt that is engageable with driving claws (31) of a driving sprocket (3). End faces (62a) of each engaging recess (62) in a belt width direction are tapered to be narrower toward an inner depth side of the crawler belt. The driving sprocket (3) has the driving claws (31) provided in an outer circumferential side of a disk-shaped member (30), which side is fitted into a space between right and left cored bar projections (63). Each driving claw (31), which is elongated greater in the lateral direction than in a circumferential direction of the disk-shaped member (30), has end faces (31a) in a lateral direction of the disk-shaped member (30). The end faces (31a) of the driving claw (31) in the lateral direction are tapered to be narrower radially outward.
