A method for absorbing vehicle's impact using a kinetic frictional force produced by dragging a surface of rolled tube, wherein impact energy of the vehicle is primarily absorbed by rolling and dragging action of a front barrier and a first dragging kinetic frictional rolling force inducing member with a kinetic friction inducing bolt inserted therein, which are sequentially inserted and installed in a front end portion of a kinetic frictional force inducing rolled tube made of a soft material, so that a maximum deceleration of the vehicle slows to 20g or less; the method comprising: while dragging the front barrier and the first dragging kinetic frictional rolling force inducing member, rolling and dragging a second dragging kinetic frictional rolling force inducing member to secondarily absorb and reduce kinetic energy, wherein the second dragging kinetic frictional rolling force inducing member has a kinetic friction inducing bolt inserted therein, wherein the second dragging kinetic frictional rolling force inducing member has a kinetic friction coefficient larger than that of the first dragging kinetic frictional rolling force inducing member and is installed at an intermediate portion of the kinetic frictional force inducing rolled tube; and while dragging the front barrier, the first dragging kinetic frictional rolling force inducing member, and the second dragging kinetic frictional rolling force inducing member, with the kinetic friction inducing bolts (42a, 42b) inserted therein, pushing, rolling, and dragging a rear barrier and a third dragging kinetic frictional rolling force inducing member having a kinetic friction inducing bolt inserted therein so that a kinetic frictional force of the vehicle becomes a maximum stop frictional force in a state in which kinetic friction coefficients of the first dragging kinetic frictional rolling force inducing member 40a and the second and third dragging kinetic frictional rolling force inducing members 40b and 40c are added, wherein the rear barrier is installed along a stopper distance S of the kinetic frictional force inducing rolled tube. while dragging the front barrier and the first dragging kinetic frictional rolling force inducing member, rolling and dragging a second dragging kinetic frictional rolling force inducing member to secondarily absorb and reduce kinetic energy, wherein the second dragging kinetic frictional rolling force inducing member has a kinetic friction inducing bolt inserted therein, wherein the second dragging kinetic frictional rolling force inducing member has a kinetic friction coefficient larger than that of the first dragging kinetic frictional rolling force inducing member and is installed at an intermediate portion of the kinetic frictional force inducing rolled tube; and while dragging the front barrier, the first dragging kinetic frictional rolling force inducing member, and the second dragging kinetic frictional rolling force inducing member, with the kinetic friction inducing bolts (42a, 42b) inserted therein, pushing, rolling, and dragging a rear barrier and a third dragging kinetic frictional rolling force inducing member having a kinetic friction inducing bolt inserted therein so that a kinetic frictional force of the vehicle becomes a maximum stop frictional force in a state in which kinetic friction coefficients of the first dragging kinetic frictional rolling force inducing member 40a and the second and third dragging kinetic frictional rolling force inducing members 40b and 40c are added, wherein the rear barrier is installed along a stopper distance S of the kinetic frictional force inducing rolled tube.