The dental floss dispenser has an inner floss cartridge chamber and a retainer head screwed to it with a pair of spaced arms (34, 36) with openings (50, 52) on the outer ends, through which the floss (F) is threaded. One passage (32) goes from the chamber (12) to the head (14) and another one (46) runs from the head (14) to a groove (48) in one of the arms. The coupling (20) between the chamber body. The head has an internal clamping device to fix one end of the section of dental floss, whilst a second external clamping and cutting device is provided for the other end of the floss section. The dental floss (F) runs from the inner clamping device, through the head (14) along the groove (48) between the arms (34, 36) and to the outer clamp.