A base material for tape and an adhesive tape

To provide a base material for a tape and an adhesive tape which can be used for an adhesive tape that can be properly adhered to not only a flat surface but also a curved surface, an uneven surface or a roughened surface, hardly causes peeling, floating or the like of an end part after adhesion, can be easily peeled when peeling, and can be easily adhered and replaced. A tape base material made of a synthetic resin and used with an adhesive layer provided on at least one surface thereof, the tape base material having a length of 80 mm and a width of 25 mm and bent in a loop shape is crushed by an indenter at a push-in speed of 3.3 mm/s in a diameter direction of the loop, And a loop stiffness which is a load value when a diameter of the loop in a push-in...