A toothbrush including a brush main body of a synthetic resin and having a bristle base and bristles of a thermoplastic resin which have been fusion-bonded to the bristle base to constitute a bristled part, the bristles constituting the bristled part at least partly comprise: tapered bristles which are bristles having split free ends, the split free ends having been tapered beforehand; tapered bristles which have a sectional shape having a core-sheath structure or islands in a sea structure; or tapered bristles in each of which a core bristle comprising a core or island part has been formed beforehand so as to be exposed at the free end. The toothbrush has excellent suitability for bristle insertion into narrow parts. It is highly effective in removing dental plaque and cleaning the teeth. It is highly easy to use in the oral cavity. It further has a highly attractive appearance.