A CB2 receptor modulator comprising an imidazole derivative represented by the general formula (I): [wherein, R1 represents optionally substituted lower alkyl or the like; R2 represents optionally substituted cycloalkyl or the like; R3 represents optionally substituted aryl or the like; and n represents an integer of 0 to 3] or a pharmaceutically acceptable salt thereof as an active ingredient, and the like are provided.