To provide a continuous boring device capable of performing boring work in high work position accuracy by eliminating influence of the deflection and a twist even in a thin or wide long sized material.

A punch 1 and a die 2 are provided above and below the long sized material A, and are mutually opposed by sandwiching the long sized material A so as not to hinder a vertical movement of the punch 1 and the die 2, and a vacuum-sucking plate 4 and a support plate 5 are respectively arranged so as to be movable in the vertical direction. The long size material A is flatly sucked to and held by the vacuum-sucking plate 4 while being sandwiched by the vacuum-sucking plate 4 and the support plate 5, and a hole is bored in the flatly held long sized material A by the punch 1 and the die 2.