Because of the airtightness of building, misuse of building materials and abuse of furniture, indoor air pollution problems have been increasingly concerned especially with apartment buildings. To improve the IAQ(Indoor Air Quality) in apartment building, this study was aimed at analyzing the factor of interior building material and furniture and calculating the ventilation rate of living room and bed room according to the surface area of interior building material and furniture in terms of VOCs(Volatile Organic Compounds) and HCHO(Formaldehyde). The results of this study are as follows; 1) In the concerned rooms, the living room has less pollution emission rate L(surface area/volume) than that of the bed room but, the living room needs more ventilation rate than that of the bed room because of built-in furniture in terms of VOCs and HCHO. 2) Built-in interior furniture is very important factor in IAQ problems of apartment building, but until now there is no provision about the built-in furniture, so that the provision must be regulated to control the IAQ. 3) To control the IAQ problem, the effective ventilation plans must be established according to the required ventilation rate by means of natural or mechanical ventilation method.