The chemical potential of substance condensed out of vapor in drop formed on soluble nucleus of colloid surfactant has been found. Both ionic and nonionic surfactants have been considered. The threshold value of vapor chemical potential was found for condensation on soluble nuclei of colloid surfactants. The regularities of thermodynamics of heterogeneous condensation it the presence of soluble surfactants have been discussed. It has been shown that micellization in the solution inside a drop with large micelle aggregation number increases considerably the threshold value of vapor chemical potential.