To provide a packaging bag with a slider opening type sealing belt wherein the presence of breakage of a sign-piece can be easily seen from the outside of the bag and to allow a slider to easily break the sign-piece when the bag is unsealed.

The packaging bag has a sealing belt (20), a slider 30 for opening and closing the belt (20), and a sign-piece (40) which is disposed on a passage route of the slider (30) so as to be broken at a first unsealing. The sign- piece (40) comprises a two-colored thin piece of which the front side and the rear side have different color tones.