To prevent the surface of a rubber crawler used for a sprocket and an idler from being cracked at its rubber part at the time of rolling, enhance its life as the rubber crawler, and furthermore, make the rolling of the sprocket and the idler smooth.

In an inner circumference driving type rubbercawler in which the crawler is provided with each core metal buried in rubber while being placed crosswise in a row at certain pitch, each pair of angle parts 12 projected at the right and left sides while each core metal 19 is being held in between at its center part, and with each driving projection 24 which is of continuous length in the width direction rather than the longitudinal direction of each core metal, and is formed out of each angle part 12, and of each rubber member 23 covering the longitudinal direction of each angle part, and each driving pin erected out of a sprocket is engaged with each driving projection 24 so as to allow driving power to be transmitted, each recessed part 26 is formed in the boundary part of each core metal 10 at the center part of the rubber crawler, which is located between the driving projections.