PURPOSE: To prevent the lowering of turning capacity and minimize the running vibration in a combine, a harvester, and other farm machines by setting the pitch of propelling lugs of a crawler belt specific times as wide as the crawler belt.

CONSTITUTION: On the periphery of a crawler belt 4, propelling lugs 8 are projected at a proper circumferential pitch, while core metals 9 are buried in the belt at the same pitch with these lugs. From these core metals 9 to the inside of the belt, a pair of right and left roller-guide projections 10 is provided, and between these core metals 9, sprocket matching holes 11 are bored. The pitch P of the propelling lugs 8 against a crawler width W is set as P=0.3W0.4W. By setting the propelling lug pitch P rationally in relation to the crawler width W, the collapsing of soil between lugs 8 is minimized for turning a machine body, and the vibration of the machine body can be suppressed for running on a dry field or a road.