The invention discloses isoxazole derivatives represented by aformula,(see formula I)in whichR1 stands for hydrogen, lower alkyl, amino, halogen, loweralkoxy and the like,R2 stands for substituted or unsubstituted aryl and the like,R3 stands for hydrogen or lower alkyl,R4 stands for substituted or unsubstituted phenyl and the like,andY stands for -CH2-, -CO-, -CH(CH3)-, -O-, -NH- and the like,or pharmaceutically acceptable salts thereof, which have excellentp38MAPkinase inhibitory action.