To provide a new bristle material for a toothbrush excellent in cleanability, durability, and gingiva massage effect, and also to provide a toothbrush using the same.

The bristle material 1 for the toothbrush is formed from a cut bristle of a synthetic resin monofilament having a core/sheath composite structure. The sheath part 3 of the synthetic resin monofilament has a multi-lobal cross-section having a plurality of recesses 4 and protrusions 5. The recesses 4 form grooves 6 in a direction of the length of the side surface along the monofilament. At least at one end of the cut bristle, the branch bristles 7 formed of the protrusions 5 are formed into a crown shape.