TOOTHBRUSH

The present invention provides a toothbrush capable of securing a sufficient bristle implanting strength and having excellent operability in an oral cavity without causing warping or whitening and cracking of a resin in a head portion of a flat wire type bristle implantation method. The toothbrush (1) includes a head portion (10) is provided with plurality of bristle implanted holes (13) on a bristle implanted surface (12), in which a bristle bundle that is configured to bundle a plurality of bristles is folded in half and implanted into the bristle implanted hole (13) using a flat wire (15), a thickness of the head portion (10) is 2.0 mm or more and 4.0 mm or less, a bristle implanted hole density of the bristle implanted hole (13) is 25 holes/cm? or more, and when an inner diameter of the bristle implanted hole is X, a thickness of the flat wire is d, and X is 0.9 mm or more and 1.3 mm or less, a relationship of 0.37 mm ? (X - d)/2 ? 0.55 mm is satisfied. Fig. 1A