The present invention provides an antifungal agent that has excellent antifungal action, and is also excellent in terms of its properties, safety, and metabolic stability. The present invention discloses a compound represented by the following formula I or a salt thereof, and an antifungal agent comprising the compound or the salt: wherein R1 represents a hydrogen atom, a halogen atom, an amino group, a C1-6 alkyl group, a C1-6 alkoxy group, or a C1-6-alkoxy-C1-6-alkyl group; R2 represents a hydrogen atom or an amino group; X, Y, Z, and W independently represent a nitrogen atom, an oxygen atom, a sulfur atom, or —CH—, provided that at least two among X, Y, and W are nitrogen atoms; the ring A represents a 5- or 6-membered heteroaryl ring or a benzene ring; Q represents a methylene group, an oxygen atom, —CH2O—, —OCH2—, —NH—, —NHCH2—, or —CH2NH—; and R3 represents a C1-6 alkyl group, a C3-8 cycloalkyl group, a C6-10 aryl group, or a 5- or 6-membered heteroaryl group, each of which may have one or two substituents.