The variety and commonality of impressions produced by the visualization of a piano piece was investigated from the perspectives of color attributes, color combinations, and impression categories. The participants in Experiment 1 （N=202） expressed their impressions of a piano piece by using five color combinations, and participants in Experiment 2 （N=30） selected color combinations that matched their impressions of the piano piece from 30 color combinations. The results of Experiment 1 indicated that color attributes of the five color combinations inclined to be bright and clear tones, or bright and muddy tones, having a high degree of lightness. Moreover, the color combinations were diverse based on the hue composition in the narrow tone range. The five color combinations were classified into 12 impression categories approximating a soft image on the Image Scale. The attributes and impression categories of the color combinations selected in Experiment 2 were nearly identical to Experiment 1. It is supposed that impressions evoked by different music types would be expressed by colors variously. The results of the present study suggest that impressions of a piano piece are reflected in color attributes, including the tone and hue, and in color combinations that are visualized in different ways.