A camera module which collects incoming dirt and dust so as to prevent the accumulation of same on an optical element of the image-capturing process includes a microscope base and an optical filter unit. The microscope base includes a supporting portion. A first gap is formed in the supporting portion. The optical filter unit filter and adhesive layer formed on the optical filter. The optical filter is bonded on the supporting portion by the adhesive layer. The optical filter comprises a filter area in the optical filter. A surface of the adhesive layer facing away from the optical filter is adhesive. A second gap is formed in the adhesive layer. The filter area is exposed from the second gap. Parts of the adhesive layer and the filter area are exposed from the first gap.