An arylamidine derivative represented by a general formula described below or a salt thereof has an excellent antifungal action and high safety, and it is useful as an antifungal agent with good pharmacokinetics and pharmacodynamic properties wherein X represents an unsubstituted or substituted lower alkylene or alkenylene group; G1 represents an oxygen atom, a sulfur atom, or an imino group; G2 represents a carbon atom or a nitrogen atom; Ra represents at least one group selected from the group consisting of a hydrogen atom, a halogen atom, and unsubstituted or substituted alkyl, cycloalkyl and alkoxy groups; R1 represents an unprotected or protected or unsubstituted or substituted amidino group; and R2 represents a substituted amino or substituted cyclic amino group, or the like.