Abstract: The present invention provides a mechanical toothbrush with a dual rotary brushing system and comprising a handle-forming body and a head fixed to the handle, which head is provided with two adjacent contra-rotating brushes of cylindrical shape and having substantially parallel axes. Each of the two brushes is driven by a flexible shaft situated in the head and supported, at least at its distal end, by a respective bearing mounted on a support that enables the two brushes to move apart one away from the other, then urging the brushes towards the other by a return effect.