The invention relates to an adjusting instrument for an exterior vision unit for a vehicle, comprising a base shaft and a housing surrounding the base shaft which is pivotable around a longitudinal axis adjustment range between at least a park position and a drive position. The adjusting instrument further comprises a driving gearwheel, a gearwheel body, and a spring. The driving gearwheel includes a face provided with an outer toothing surrounding the base shaft, defining a face height within which a web part of the gearwheel body extends in a transverse plane with respect to the base shaft. The spring surrounds the base shaft and is supported on a support surface of the gearwheel body, exerting a force on the driving gearwheel along the longitudinal axis. The support surface lies recessed in an axial direction with respect to the transverse plane, such that the spring reaches through the transverse plane.