The method for prescribing the site of the first buckling lobe in the axial impact of the tubular structure is proposed. The inertia force induced by the solid mass attached to the tube during the impact is exploited to trigger the first buckling lobe. When the tube with the solid mass undergoes a large acceleration, the inertia force of the solid mass is expected to bend on the tube wall. In the experiment, the rectangular solid mass was attached to the aluminum alloy square tube. The tube fixed to the drop-hammer was impacted against the stationary rigid plate at the velocity of 5 or 7.7 m/s. For the case of the tube without the solid mass, the site of the first buckling lobe varied and the slight wavy plastic deformation remained further than the buckling lobes. On the other hand, when the tube with the solid mass was impacted, the onset of the first buckling lobe was observed at the portion where the solid mass was attached and the wavy deformation stated above was suppressed. The corresponding computation was also conducted using the dynamic explicit finite element method. The result showed a good agreement with the experimental one.