There is disclosed an analytical element comprising a support; a reagent layer which is positioned on one side of the support and contains a reagent reactive with a component in a fluid sample; and a porous spreading layer which is positioned on the reagent layer on the opposite side to that of the support for permitting the component in the fluid sample to permeate into the reagent layer; wherein at least one layer contains 5% by weight or more of a polymer formed by, (i) a copolymerizable ethylenically unsaturated acid with (ii) a copolymerizable ethylenically unsaturated monomer. The analytical element according to the present invention can determine a component in a fluid sample quantitatively.
