Abstract: A bias tape supply device comprises a circular housing part made of synthetic resin for housing a bias tape and a guide part made of synthetic resin for delivering the bias tape from the housing part.The housing part includes a top circular wall, a bottom circular wall, a cylindrical circumferential wall, and a magnet fixed outside the bottom circular wall.The side walls gradually decrease in height from the base end of the guide part to the tip thereof.The first side wall located adjoining the housing part is adapted at the tip thereof to be lower in height than the second side wall and is substantially triangle-shaped in a section thereof at the tip thereof.Two projections are provided on the tip of the second wall, and a slit is notched in the second side wall located between the two projections.The bottom circular wall of the housing part and the lower wall of the guide part are kept horizontal and formed integrally with each other.