The present invention aims at providing an isoxazoline derivative and a pharmaceutically acceptable salt thereof, both having an excellent herbicidal effect and an excellent selectivity between crop and weed.The isoxazoline derivative of the present invention is represented by the following general formula: wherein R1 is a haloalkyl group; R2 is a hydrogen atom, an alkyl group, or the like; R3, R4, R5 and R6 are each a hydrogen atom, or the like; Y is a pyrrolyl group, a pyrazolyl group, an isothiazolyl group, an oxazolyl group, an imidazolyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a triazolyl group, an oxadiazolyl group, or the like; and n is an integer of 0 to 2.