A chamber method using ADPAC (ADvanced Pollution and Air quality Chamber) has been established by Japanese Industrial Standards Committee for measuring emission rates of VOCs from building products. The active methods such as ADPAC or FLEC (Field and Laboratory Emission Cell) have been applied for precise measurement. However, these methods occasionally cause problems such as noise of pump, heavyweight of equipment, and so on. To solve these problems, a new passive method using ADSEC (Advanced Diffusive Sampling Emission Cell) was developed to measure emission rate using a diffusive sampler. In this study, VOCs emission rate were investigated using ADSEC and ADPAC (20L) to examine the accuracy of passive method. It was confirmed that active and passive methods have similar decrease tendency under all conditions.