Abstract: The problem to be solved by the present invention is to provide a monolith adsorbent which can adsorb a target sample easily in a short time or regardless of whether the amount of the sample is small or large and extract the sample with a small amount of solvent, and easily secure the sample necessary for analysis, and a method and an apparatus for adsorption and retention using the same. The present invention, as the means for solving the problem, is a monolith adsorbent formed by allowing a monolith structure body to contain an adsorbing material such as activated carbon or graphite, exposing the adsorbing material on the surface of the structure body and further surface-treating the surface of the monolith structure body with a hydrophobic or hydrophilic compound or a resin.