To provide an indoor simple installation type negative pressure type isolation room, capable of preventing infection spread to the circumference when a patient of highly-virulent infection disease such as new flu or bird flu is received in doors such as a ward of a hospital or the like.

A space part 2 including a bed 1 of an inmate is entirely closely enclosed with a metal or synthetic resin-made frame member 6 which is easy to assemble and disassemble and a synthetic resin-made flexible cover sheet 8 and mat sheet 10 having high air-tightness to form a sealed living room 3, and an air supply unit 11 and an air exhaust unit 12 each provided with an air filter are allowed to communicate with the living room 3. Air volume adjustment is performed with the air supply and exhaust units 11, 12, whereby the air is highly purified while maintaining the level of negative pressure in the living room of the inmate to prevent and respond to the secondary infection of the inmate reduced in resistance.