To provide a header slip in simple constitution.

On the head part of the header slip formed into a strip piece shape from relatively thick paper or a synthetic resin thin plate not to be easily bent, a header part where a period such as an arrival period and a shelf filling period of a book is displayed by a color and a numeral is provided. At the upper part of the header slip, a clamp supporting piece in a tongue piece shape continued to the header part at a boundary part with the header part is formed by a cutting part cut in an upward groove shape with left and right upper ends positioned at the boundary with the header part. To the optional part of the header slip, a magnetic introducing gold short wire for preventing shoplifting is attached.