To suitably perform automatic direction control by balancing the brake pressure of left and right crawlers by correcting the degree of brake effect concerning a crawler type mobile farming machine provided with the travel transmitter of a single brake mechanism.

This device is provided with a brake pressure regulating means for regulating brake pressure to one of left and right crawlers of the single brake mechanism to a proper value, a corrected brake pressure storage means for storing corrected brake pressure into a non-volatile memory after regulation, brake pressure generating means for operating the single brake mechanism with the corrected brake pressure read out of the corrected brake pressure storage means. Thus, since the brake pressure of one of left and right crawlers is completely regulated, it is necessary only for the other brake to be corrected and, at the time of direction control, the degree of turning can be easily adjusted.