To provide a new adamantane derivative useful as an additive for improving the etching resistance and heat resistance of a resist material for far-ultraviolet resist.

The adamantane derivative is represented by formula (1), has a structure in which adamantane skeletons and a 1-12C monovalent chain or alicyclic hydrocarbon group are bonded to the molecule through alkylene-bonded ester linkages, and is exemplified by 1-adamantyl-1-adamantaneacetate. In formula (1), each R1 is a monovalent chain or alicyclic hydrocarbon group optionally having a specified substituent; each R2 is a substituent such as a hydrogen atom or a 1 to 6C alkyl group; each R3 is a hydroxy group, a halogen atom, or a 1 to 6C alkyl group; m is an integer of 0 to 3; and n is an integer of 1 to 3.