To provide a method for constructing a soundproof chamber, which facilitates various kinds of work when the soundproof chamber is assembled and disassembled, and enhances the durability of the same.

There is provided a sound insulation panel 19 which consists of a pair of reinforcing materials 21, 21 each formed of a lead plate, and a hollow body 22 arranged between the reinforcing materials 21, 21 in one body therewith, for encapsulating air therein. The hollow body 22 is inflated according to filling of air therein, whereas it is deflated according to emission of the air therefrom. Further, the hollow body 22 is inflated along surfaces of the respective reinforcing materials 21 while air is encapsulated therein.