The present invention provides an agent for modulating CB2 receptor, which containing, as the active component, an imidazole derivative of the following formula (I)[wherein, R1represents an optionally substituted lower alkyl group etc. ; R2represents an optionally substituted cycloalkyl group etc. ; R3represents an optionally substituted aryl group etc. ; n represents an integer of 0~ 3], or the pharmaceutically acceptable salt thereof.提供含有如下式(I)咪唑衍生物[式中R1為可有取代基之低烷基等,R2為可有取代基之環烷基等,R3為可有取代基之芳基等,n為0~3之整數]或其藥理學容許鹽為有效成分之CB2受體調節劑等。