An electric brush powered by mains electricity includes a power converter, an upper housing, a lower housing, a push button switch, an electric motor, a speed reducer, an output rotation shaft, an adapter, a brush head and a seal ring. The speed reducer and the electric motor of a mechanical rotation part, and the push button switch and a low-voltage power socket of a circuit part are all mounted in an airtight housing inner cavity. Meanwhile, the brush head and a main body part are in a plugged-in connection. The brush head can be randomly changed to realise multiple purposes, so that the defects of the poor waterproofing performance and the single function of existing electric brushes can be thoroughly solved, thereby greatly improving the reliability and the convenience of the product.
