Device for nondestructive viscoelastic characterization of materials, comprising: - a tubular shell, almost cylindrically shaped and such dimensioned that it can be grasped by hand, having inside a through-recess provided with at least a first narrowing provided inside the axial development of said inner recess and a second narrowing provided at the upper base of said shell; - a first rod, provided at an end with a cap and a tip projecting through the cap and at the other end with a base of ferromagnetic material, fastened so that it can slide inside said shell between a first position, in which said tip does not project through the lower base of said shell, and a second position, in which said tip projects through said lower base, said rod being provided with a stop configured to abut with respect to said first narrowing, - a first spring configured to push said tip of said rod outwards, from the side of said lower base; - a displacement sensor configured to read the displacement of said first rod while sliding along the tubular shell; - a button, sliding between a first and a second position inside said shell with a stroke greater than the one of said first rod, and integral to a second rod coaxial to said first rod, said second rod being provided, at the end facing said first rod, with a magnet; - a second push spring, with elastic rigidity greater than said first spring configured to push said button to the upper portion of said tubular shell, said device being configured so that after pressing the button said magnet comes in contact to said base of ferromagnetic material, thus fastening it by magnetic attraction, and so that after the button is released, said base of ferromagnetic material is separated from said magnet when said stop prevents another movement of said first rod, thus allowing said first rod to fall freely always at the same height. - a tubular shell, almost cylindrically shaped and such dimensioned that it can be grasped by hand, having inside a through-recess provided with at least a first narrowing provided inside the axial development of said inner recess and a second narrowing provided at the upper base of said shell; - a first rod, provided at an end with a cap and a tip projecting through the cap and at the other end with a base of ferromagnetic material, fastened so that it can slide inside said shell between a first position, in which said tip does not project through the lower base of said shell, and a second position, in which said tip projects through said lower base, said rod being provided with a stop configured to abut with respect to said first narrowing, - a first spring configured to push said tip of said rod outwards, from the side of said lower base; - a displacement sensor configured to read the displacement of said first rod while sliding along the tubular shell; - a button, sliding between a first and a second position inside said shell with a stroke greater than the one of said first rod, and integral to a second rod coaxial to said first rod, said second rod being provided, at the end facing said first rod, with a magnet; - a second push spring, with elastic rigidity greater than said first spring configured to push said button to the upper portion of said tubular shell,