An automatic veering structure for a floor cleaning apparatus comprises a driving wheel set to control moving direction of the floor cleaning apparatus, an auxiliary wheel set and a buffer module. It also has a detection module to detect whether the auxiliary wheel set is suspended in the air and whether the buffer module bumps into an obstacle, then output a first detection signal and a second detection signal to a control module to determine whether to trigger the driving wheel set to drive the floor cleaning apparatus to veer to prevent the floor cleaning apparatus from suspending and falling, or stopping moving when encounters the obstacle. Thus the lifespan of the floor cleaning apparatus is lengthened and cleaning efficiency improves.