An embodiment of the present invention includes a method for chemically modifying inner surfaces of channels capable of further regulating characteristics of the internal environment of channels, by forming a polymer complex having a specific channel group B, the channel environmental characteristics of which are regulated by substituents A, followed by utilizing the channels of the channel group B as a reaction field to convert the substituent A to a different substituent. The method may comprise including a guest molecule in the channel of the channel group B in which the substituents A are arranged; and reacting the guest molecule with the substituent A in the channel to convert the substituent A to a substituent A′, and to arrange the substituent A′ regularly directing to the inside of the channel of the channel group B or any channel of other channel groups.