In recent years, the control of airborne ions has become one of the important research items of indoor environment. Generally, it is quite difficult to get the sample of airborne ions, because their electric charge might be discharged if they touch any surface. The authors considered that it would be possible to evaluate how many of the sampled molecules had existed as ions in air, if the relationship between airborne ion's concentration and its adsorption rate to the surface was clarified. In this research, absorption of condensed organic compound ions on the substrate faced to the corona discharge type ionizers was studied, and the model for the adhesion rate of ions on charged plate surface was proposed. This model consists of the Langmuir-type surface absorption and the molecular sedimentation models, and the model contains electrostatic diffusion and the electrophoresis. The authors also added the influence of the fragmentation of target molecules to this model. As a result, the predictions estimated by this model agreed well with the experiments.