Conventional toothbrushes must be destroyed and incinerated as refuse after use, resulting in a waste of resources and generating carbon dioxide. A toothbrush is provided with: a toothbrush body having a head formed in an oval-ring shape, the head having a female part or male part being aligned with the toothbrush body and disposed at a connection region connecting to the toothbrush body; and a replaceable bristle part having a male or female part being releasably coupled to the male part or female part of the head. Thus, after an appropriate period of use, the replaceable bristle part can be easily exchanged. The coupling of the female part or male part prevents the fore-end of the toothbrush from shaking laterally during tooth brushing. The toothbrush provides a toothbrush body for repeated reuse, and contributes significantly to the reduction of carbon dioxide by a reduction in refuse.