It is intended to provide a substance having an effect of shrinking pores by analyzing the mechanism of making pores perceptible and compositions such as a skin preparation for external use which exerts the above effect to thereby make pores imperceptible. As means for solving these problems, there are provided a parakeratosis inhibitor and a pore-shrinking agent comprising an antagonist to an excitatory cell receptor, for example, a glutamate receptor such as N-methyl-D-aspartic acid receptor or an ATP receptor such as P2X receptor, or an agonist to an inhibitory cell receptor such as a γ-aminobutyrate receptor such as bicuculline-sensitive receptor having the Cl-channel therein or glycine receptor, as well as a skin preparation for external use aiming at inhibiting parakeratosis and a skin preparation for external use aiming at shrinking pores each containing such an antagonist to an excitatory cell receptor or an agonist to an inhibitory cell receptor as described above. Owing to the effects of inhibiting parakeratosis and shrinking pores, the skin can be maintained in a healthy state without perceptible pores.
