Provided is a dental floss holder in which the type of floss thread and the degree of tension thereof can be easily changed and the workability of the user is good. The dental floss holder includes a rod-like handle portion for a user to grip, a head portion to which a dental floss is locked, and a constricted portion connecting a distal end of the handle portion and the head portion, the constricted portion formed so as to be reduced with respect to a connection part of the handle portion and the head portion adjacent to the constricted portion in a width direction and/or a thickness direction of the connection part. A recessed portion extending in a thickness direction of the head portion is formed on a distal end surface of the head portion, and a notch portion is formed in a longitudinal direction from the recessed portion, and the notch portion extends to the constricted portion.