A belt driving control device includes an endless belt looped over a plurality of supporting rollers, a driving source supplying rotational driving force the supporting rollers, a detecting section detecting a periodical thickness deviation of the endless belt in a circumferential direction of the endless belt and carrying out data sampling for detection of the thickness deviation simultaneously with rotation of the endless belt, a memory storing data on the thickness deviation obtained based on the data sampling, and a control section controlling drive of the driving source such that the detected thickness deviation of the endless belt is canceled out based on the data on the thickness deviation stored in the memory, and such that the endless belt is driven to travel one rotation upon detecting a predetermined condition to carry out the data sampling for one rotation and update the stored data with new data.