The invention discloses an automobile rim edge evenness detecting device. The problems that a rim and a detecting instrument need to be adjusted when traditional automobile rim edge evenness is tested, and detection efficiency is improved while ensuring detecting accuracy at the same time are solved. The automobile rim edge evenness detecting device comprises a placing mechanism and a detecting mechanism installed on the placing mechanism. A rotating connecting hand lever is arranged at the top of the detecting mechanism. The placing mechanism mainly comprises a base of an arc structure and side seats located on the outer walls on both sides of the base. A slot of an inner sunken structure is formed in the top of the base, a groove of which the radian is matched with the base is formed inthe middle portion of the slot, and a plurality of steel balls distributed evenly are embedded into the groove. A supporting plate arranged vertically is welded to the bottom of the base, and two fixing holes are formed in the side walls of the supporting plate. The automobile rim edge evenness detecting device can quickly and accurately complete the detection of the inner wall evenness of the rimedge in work, and is high in stability and convenient to operate.