The dynamic surface tension for the adsorption of Brij58 from its micelle solution is measured by the strip method, created by Rillaerts, at a continuously expanding surface with a constant surface dilatation rate. With the assumption that the perturbations for the monomeric and micellar concentrations are proportional with the nonperturbated concentrations, the influence of the micellar presence on the adsorption process is attributed to an apparent diffusion coefficient depending on the ratio of the monomer in micellar and free forms. An experimental apparent diffusion coefficient is given by the proposed equation, describing the jump in surface tension as a function of surface dilatation rate. A good agreement between theory and experiment is observed.