An edge exposure unit includes a projector, a projector holding unit, a substrate rotating unit, an outer edge detecting unit and a surface inspection processing unit. Each component of the projector holding unit operates to move the projector in an X direction and a Y direction. The projector irradiates a peripheral portion of a substrate with light transmitted from a light source for exposure through a light guide. Edge sampling processing is performed based on distribution of an amount of light received in a CCD line sensor of the outer edge detecting unit. Surface inspection processing is performed based on distribution of an amount of light received in a CCD line sensor of the surface inspection processing unit.