In recent years, indoor formaldehyde (HCHO) and volatile organic compounds (VOCs) from interior finishing material are recognized as one of serious potential risks against human health. Authors carried out experiment to quantify the emission rates of HCHO and total VOCs (TVOC) from main interior finishing materials of multi-family houses on various conditions of temperature and relative humidity. The acquired data shows the tendency that higher the temperature and humidity are, higher emission rates are obtained'except those of HCHO from vinyl-wall finishing. And predictive calculation of concentration of HCHO and TVOC in a house that has been already measured was carried out using these data. As a result, the tendencies are shown that calculated values are about 4 times as much as measured ones in HCHO concentration, and that calculated values are approximation of measured ones in TVOC concentration compared with HCHO. It seems that this was caused by the re-adsorption mechanism. Therefore, the re-adsorption mechanism must be indispensable to the prediction of the concentration of especially HCHO.