(57) A folding toothbrush capable of shaping the hair edge of the brush automatically. The toothbrush includes a front handle (4) with a hair-planted part (2) and a rear handle (3) with a case part (5). Both handles (3, 4) are rotatably connected by pivots and connection holes (6, 7). When the handles (3, 4) are extended, they are aligned in a straight line. When the handles (3, 4) are folded, the hair-planted part (2) of the front handle (4) is received in the case part (5) of the rear handle (3). The case part (5) includes slanting case side (22), front (24) and rear walls (25). The hair edge is inwardly bent by the slanting case walls in the folded state. The hair edge is naturally shaped by the case walls.