To obtain a pressure adhesion paper having high quality, excellent in water resistance and free from the occurrence of falling off or bleeding of printed letters, soiling, etc., even in the case where a part printed with an injet printer is got wet with water by coating an adhesive composition consisting of a specific component on a confidential surface.

An adhesive composition is prepared by compounding (A) a cold sealing agent (preferably, a natural rubber latex, etc.) and (B) finely pulverized powder of a mineral (preferably, super-fine amorphous silica powder having a particle size of ≤3μm) with (C) a cationic polymer having a zero or minus electric charge at a high pH region (e.g. N-hydroxyalkylpolyethyleneimine), (D) a polyphosphoric acid salt (preferably, tripolyphosphoric acid salt, etc.) and (E) a polyvalent metallic salt (preferably, a calcium salt, etc.). The adhesive is coated on a confidential surface of a sheet. Further, 20-40 pts.wt. component C and 12-30 pts.wt. component D in terms of the anhydrous salt are preferably compounded to 100 pts.wt. component A. Furthermore, it is preferable that the component D is compounded prior to the component E since this can prevent the decomposition of the component A.