Abstract: In an integral multilayer analytical element which comprises a first nonfibrous porous layer, a second nonfibrous porous layer, and a fibrous porous layer superposed in this order to a water-impermeable light-transmissive support, the above three porous layers are integrally laminated to each other substantially closely by an adhesive disposed partially so as to form through microspaces to the degree not to interfere approximately uniform permeation of liquid, a reagent composition to produce an optically detectable change in the presence of an analyte is incorporated into at least one of said three porous layers, the improvement comprising that the void volume and the void volume per unit area of the first nonfibrous porous layer is less than a half of the void volume per the same unit area of the second nonfibrous porous layer.