To provide the travel driving device of crawler type vehicle capable of extending wear life of a sprocket and a bush, furthermore easily replacing these wear members.

Abutment members 26 are detachably fixed at facing surfaces of sprockets 10 of track blocks 24, tip parts of the sprockets 10 are brought into contact with the abutment members 26, so that clearances C between bushes 22 of crawler tracks 20 and tip bottom parts 14 of the sprockets 10 are secured. The tip bottom parts of the sprockets 10 and front face parts of the abutment members 26 have face parts 13, 27 which contact with each other when sprockets 10 turn.