A belt driving device comprising: an endless belt that is stretched over and supported by a plurality of supporting rollers (63, 67, 68, 69, 71) including a steering roller for correcting belt meandering; an inclining mechanism that is configured to perform an operation of inclining the steering roller by a driving force from a driving source; a belt-width direction displacement detecting unit that is configured to detect displacement of the endless belt in a belt-width direction; an inclination controlling unit that is configured to determine an inclination amount of the steering roller based on a detection result obtained by the belt-width direction displacement detecting unit, and to control the operation of the inclining mechanism to incline the steering roller by the inclination amount such that meandering of the endless belt is corrected by changing the inclination amount of the steering roller; a displacing member that is displaced integrally with the steering roller according to the inclination amount of the steering roller; and a position detecting unit that is configured to detect a position of the displacing member when the steering roller is in a predetermined reference inclined position, wherein the inclining mechanism includes a wire, a tensile force applying unit that is configured to apply a tensile force to the wire, and a wire driving member that is configured to move the wire by an amount corresponding to a driving amount of the driving source, the steering roller is configured to be inclined according to a movement of the wire, and the inclination controlling unit is configured to control the operation of the inclining mechanism by controlling the driving amount of the driving source, wherein the inclination controlling unit is configured to drive the driving source in order to bring the steering roller to the reference inclined position based on a detection result obtained by the position detecting unit, wherein the predetermined reference inclined position is updated every time predetermined adjustment timing arrives, and wherein an amount by which the inclining mechanism is operated when the inclined position of the steering roller is at the reference inclined position is used as an operation reference. an endless belt that is stretched over and supported by a plurality of supporting rollers (63, 67, 68, 69, 71) including a steering roller for correcting belt meandering; an inclining mechanism that is configured to perform an operation of inclining the steering roller by a driving force from a driving source; a belt-width direction displacement detecting unit that is configured to detect displacement of the endless belt in a belt-width direction; an inclination controlling unit that is configured to determine an inclination amount of the steering roller based on a detection result obtained by the belt-width direction displacement detecting unit, and to control the operation of the inclining mechanism to incline the steering roller by the inclination amount such that meandering of the endless belt is corrected by changing the inclination amount of the steering roller; a displacing member that is displaced integrally with the steering roller according to the inclination amount of the steering roller; and a position detecting unit that is configured to detect a position of the displacing member when the steering roller is in a predetermined reference inclined position, wherein the inclining mechanism includes a wire, a tensile force applying unit that is configured to apply a tensile force to the wire, and a wire driving member that is configured to move the wire by an amount corresponding to a driving amount of the driving source, the steering roller is configured to be inclined according to a movement of the wire, and the inclination controlling unit is configured to control the operation of the inclining mechanism by controlling the driving amount of the driving source, wherein the inclination controlling unit is configured to drive the driving source in order to bring the steering roller to the reference inclined position based on a detection result obtained by the position detecting unit, wherein the predetermined reference inclined position is updated every time predetermined adjustment timing arrives, and wherein an amount by which the inclining mechanism is operated when the inclined position of the steering roller is at the reference inclined position is used as an operation reference.