An excellent potential-dependent cation channel inhibitor or an excellent masking agent is provided. Disclosed is a method for inhibiting a potential-dependent cation channel or a method for masking olfaction, both of which include administering an adamantane derivate represented by the following formula (1) or a salt thereof [wherein R′ and R2 are identical with or different from each other, and each represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms； and X represents —OH, —R3—OH (wherein R3 represents an alkylene group having 1 to 6 carbon atoms), —NH2, —R4—NH2 (wherein R4 represents an alkylene group having 1 to 6 carbon atoms), —COOH, —R5—COOH (wherein R5 represents an alkylene group having 1 to 6 carbon atoms), —CO-R6 (wherein R6 represents an alkyl group having 1 to 6 carbon atoms), —CO—R7—COO—R8 (wherein R7 represents an alkylene group having 1 to 6 carbon atoms, and R8 represents an alkyl group having 1 to 6 carbon atoms), or —NHCO—R9 (wherein R9 represents an alkyl group having 1 to 6 carbon atoms)].
