To scavenge a harmful formaldehyde released indoors by laminating a decorative treatment layer and a surface protecting layer sequentially on the upper face of a base material sheet and forming the surface protecting layer of a curable resin coating containing a photocatalyst.

The decorative sheet 1 is structured of a decorative treatment layer 3 consisting of a solid ink layer 3a and a pictorial pattern ink layer 3b laminated on the upper face of a base material sheet 2 and further a surface protecting layer 4 formed of a curable resin coating containing a photocatalyst laminated on the decorative treatment layer 3. Therefore, formaldehyde which is generated from an adhesive or the like to be used for bonding a base material as a substrate material of ceiling material, flooring material, wall material or the like or the decorative sheet 1 to be laminated on the base material or applying a wall paper and released indoors, is decomposed by the photocatalyst contained in the surface protecting layer 4. Thus it is possible to lessen a pungent smell generated by the formaldehyde and thereby always maintain well- hygenic environments indoors.