Abstract: A prefabricated dental floss device comprises a dental floss holder (10), having the general shape of an elongate rod-like body and consisting of two interconnected but easily separable holder portions (12, 13) , and a piece of dental floss (11), received in a cavity (15) in the dental floss holder (10) and anchored to the two holder portions (12, 13) with opposite end portions thereof and adapted to become uncovered along the major portion of its length when the holder portions (12, 13) are separated from each other. Said cavity is formed by a narrow groove (15), running in the longitudinal direction of the holder (10) and extending into the holder (10) from one side of the holder, said groove (15) containing the dental floss piece (11) within the same in a position adjacent to the bottom of said groove, the end portions of the dental floss piece (11) being permanently fixed to the holder (10) at places (16) located near mutually opposite ends of the holder.