An image reading apparatus for reading a document has an image sensor unit, which
is moved along a platen glass in a sub-scanning direction, mounting an LED, a light
guide and a sensor. A white reference panel for use of shading correction is provided
on the platen glass on the side thereof opposite the image sensor unit. Light shield
plates are provided on the platen glass on the side facing the image sensor unit
along both sides of the white reference panel.
