PURPOSE: To prevent a trouble from taking place, by forming ribs in the outside part of the inner peripheral surface of a track belt so that mud gripped by the track belt may be smoothly discharged outside of the track belt without the mud being massed into large blocks.

CONSTITUTION: A belt body 1 made of resilient materials is formed into an endless shape. A plurality of ribs 2 are formed at equal intervals on the inner peripheral surfaces of both side sections 1b, 1b' which are laid both sies, in the widthwise direction W, of a middle section 1a along the longitudinal direction of the belt body. Further, engaging holes 3 for sprockets are formed in the middle section 1a of the belt body with orthogonal core metals 4 being embeded between these holes 3. When mud A is gripped in the belt body, the mud A is discharged outside ot the belt body under action of the ribs 2 before the mud A is massed into a large block.