The present invention relates to a rotating electric toothbrush comprising: a main body having a receiving space formed therein, a driving means received in the interior of the main body and providing a rotational force, a toothbrush handle having one end detachably coupled to the driving means, and receiving a rotational force of the driving means to be rotated, a support means coupled to the outer peripheral surface of the other end of the toothbrush handle and having plate-shaped support bodies made of a ductile material and radially formed to be spaced apart from each other, and a plurality of toothbrush bristles implanted between the support bodies. The present invention has a structure in which the toothbrush bristles are radially implanted on the outer peripheral surface of the end of the cylindrical rotating toothbrush handle, thereby removing food leftovers sandwiched on a tooth surface or at an interdental gap without damage of gums, and more surely removing dental plaque from the tooth surface due to silicon bristles implanted between the toothbrush bristles. Further, the silicon bristles implanted between the toothbrush bristles support the toothbrush bristles, thereby preventing deformation of the toothbrush bristles, and a space for receiving toothpaste is formed between the silicon bristles, thereby preventing the toothpaste from easily slipping off. Further, a tongue cleaner, which is detachable and made of a silicon material, is further comprised, thereby easily cleaning a tongue.