Disclosed is a dental floss holder which can control tension of dental floss which may be stretched or weakened during usage of the dental floss and prevent the tension of the dental floss from being decreased during usage of the dental floss by protrusions formed on a tension control portion. According to the present invention, there is provided a dental floss holder capable of controlling tension, the dental floss holder comprising: a body in which a head, to which a part for directly removing foreign matters of teeth from a dental floss is suspended, is provided at a front end thereof, a winding hole is through-formed in the middle thereof, and a locking pole which can be elastically deformed is formed around the winding hole; and a winding wheel which is inserted to the winding hole of the body to be rotatably provided, fixed when a part of the locking pole is suspended, and pulls the dental floss to maintain predetermined tension while rotating together when a part of the dental floss is suspended, in which the locking pole is formed in a cantilevered shape which is elastically deformable based on one end thereof, the locking protrusions are formed at the front end thereof to protrude in a longitudinal direction of the locking pole, locking grooves are grooved at predetermined intervals at a cylindrical insertion portion of the winding wheel along a trajectory which comes in contact with the locking protrusions while the winding wheel is rotated so that the locking protrusions are inserted to the locking grooves to fix the winding wheel.