A head module (2) capable of reciprocal rotation for an electric cleaning apparatus, comprising a cleaning element (21), a head module housing (22), a head module driven rod (23) disposed in a hollow head module housing inner cavity (222) of the housing (22), the driven rod (23) being provided with a hollow cavity (239) for accommodating a drive shaft (11)； at least one driven rod gap (231) provided in a region surrounding the hollow cavity body (239)； at least one housing inner side notch (221) distributed on a side wall of the housing inner cavity (222), for accommodating a corresponding driven rod protrusion (233) disposed on the driven rod (23), the driven rod (23) further comprising a partially cylindrical or conical cavity body region (238). The diameter of the region (238) or the greatest diameter of a joining portion corresponding to the region (238) is less than the diameter of a cylinder region (113) of the drive shaft (11). When the drive shaft (11) is not yet inserted into the head module driven rod (23), there is a gap (240) between the housing inner side notch (221) and the driven rod protrusion (233) and perpendicular to a direction of the axis of rotation of the drive shaft (11) (L1). The length of the gap in the direction perpendicular to a direction of the axis of rotation of the drive shaft (11) (L1) is greater than or equal to the amount of single-side interference between the driven rod (23) and the drive shaft (11) of the head module.
