Application of the present invention enables quantification of fractions of candidate pharmaceutical compounds (a parent compound and its metabolites), one excreted to the basolateral (Basal/Basolateral)-side via transporters and by diffusion, one excreted to the lumen (Apical)-side, and one remained in the cells. This enables determination of the total amount of the administered candidate pharmaceutical compounds and the distribution ratio of the fractions. The kinetics of the administered candidate pharmaceutical compounds can be evaluated, thereby enabling in vitro screening of an enormous number of candidate pharmaceutical compounds for drug candidates exhibiting the efficacy. The object of the present invention is to provide an apparatus and method for understanding a total picture of pharmacokinetics in vitro by quantifying a fraction of basolateral (Basal/Basolateral) efflux, a fraction of lumen (Apical)-side excretion, and a fraction remaining in a cell of a drug which has been administered to the cell to determine the distribution ratio of each fraction.