To provide a tension adjusting clamp apparatus capable of easily attaching a skin material, capable of preventing the generation of wrinkles in a molding material or the excessive elongation of the molding material, capable of shortening a molding material arranging time and capable of making a slide stroke constant.

A tension adjusting clamp apparatus is equipped with a molding material fixed stand 10, the clamp movable part supported on the fixed stand 10 in a rotatable manner and the slidable engaging part 30 provided to the clamp movable part and the slidable engaging part 30 is constituted so as to be made adjustable in tension by an adjusting screw 60 and, even if tension is changed by the adjusting screw 60, the position of the engaging part 30 is not changed.