When one experinces an architectural space, he/she perceives various impressions. The purpose of this paper is to quantitatively clarify the relationship between the impression perceived on a photo of an architectural internal space and the phsical features of its color image. For fifty sample color images of internal space, we have performed a questionaire concerning what impression he/she acquires for each image by asking him/her to choose one of the impression words from a pair of antonyms. Also, we have computed color and texture features of photos. Here we used two-dimensional wavelet transform to obtain texture features while Lab-color space is used to extract color features. We then applied a decision-tree algorithm in order to derive interpretable and meaningful correlation of the impression words and image features. As a result, for images for which a majority of people had the same impression, we have found an interesting, interpretable common feature among the images.