The present invention provides isoxazole derivatives represented by the following formula (I): (wherein R1 represents a hydrogen atom, C1-C20 hydrocarbon group or —C(═O)OR1a (wherein R1a represents a C1-C10 alkyl group, etc.); R2 and R3 represent a hydrogen atom, halogen atom, hydroxy group, C1-C20 alkyl group or C6-C20 aryl group, etc.; R4 represents a hydrogen atom, halogen atom, hydroxy group, cyano group, nitro group, amino group, C1-C20 hydrocarbon group, C1-C10 alkoxy group, C1-C10 acyl group, 5- to 7-membered heterocyclic group, etc.; R5 represents a hydrogen atom, halogen atom, hydroxy group, optionally substituted C1-C20 hydrocarbon group, C1-C20 alkoxy group, 5- to 7-membered heterocyclic group, etc.; and, n represents 0, 1, 2, 3 or 4), and a process of producing the same. The compounds are useful as intermediates for synthesis of pharmaceutical compounds, agricultural chemicals, dye compounds, etc. having the isoxazole skeleton.