PURPOSE: To secure an effect of thermal insulation and soundproofing of opening areas, such as a window, or either effect of thermal insulation or soundproofing, or a plurality of simultaneous effects at a low cost, and easily.

CONSTITUTION: This invention relates to an indoor shutter, which is provided with both sealing and locking mechanisms in its inner contact areas which are designed to shut off the penetration of air into a sash installed to an opening, thereby forming an airtight curtain 2 which comprises a curtain 2, a curtain case 1, a guide rail 3, a weight bar 4 and a catch bar 7. An air layer is formed between the sash and the curtain 2 installed to the opening where the opening is insulated by using the insulation effect of the air layer and at the same time, the opening is soundproofed and sun-shaped as well.