In this study, we propose the quantitative evaluation method of acoustic quality by using electroencephalogram (EEG). We analyze the EEG observed when subjects are listening to music by 3 kinds of stereo speaker system with different acoustic property. In this paper, as the first step of quantification, we analyze whether the difference of acoustic quality appear EEG by principal component analysis, analysis of variance and Fisher discriminant analysis. As a result, we confirmed that 1st principal component of EEG contains the imformation of acoustic quality evaluation which we can not obtain from questionnaires, and the possibility that we can use EEG for quantitative evaluation of acoustic quality.