2-Aryl imidazoline derivatives are provided that are useful as anti-obesity agents or the like. A compound represented by Formula (I) or a pharmaceutically acceptable salt thereof: wherein R1 and R2 each independently represent a hydrogen atom, halogen, C1-6alkyl, or the like R3a, R3b, R4a and R4b each independently represent a hydrogen atom, C1-6alkyl, or haloC1-6alkyl and Ar represents aryl, wherein the aryl may be substituted with 1 to 3 substituents such as halogen, cyano, C1-6alkyl, haloC1-6alkyl, C1-6alkyloxy, haloC1-6alkyloxy, hydroxy, amino, monoC1-6alkylamino, diC1-6alkylamino, and C1-6alkyloxy-carbonyl.