To provide a thermal transfer type image protecting sheet member reduced in curl properties even in a transfer work environment under a high humidity condition and preventing the lowering of the feed properties of a laminator caused by the curling of the protecting sheet member at the time of lamination of protective coating to an image printed sheet.

This thermal transfer type image protecting sheet member 1 is composed of a thermal transfer type image protecting sheet 2 obtained by laminating at least one thermal transfer resin layer 2h, which is peelable from the surface of a support 21, on the support 21 and a backup sheet 3 having a dimensional shape same to or larger than that of the thermal transfer type image protecting sheet and bonded to the end part of one side of the thermal transfer type image protecting sheet and characterized in that the backup sheet 3 comprises one side glossy paper. The density of one side glossy paper is especially preferably set to 0.8 g/cm3 or below.