The purposes of this study are to present the criteria for a sensibility rating scale for measuring the general public's perception of museums' spatial environment, particularly lobby space, through an empirical analysis; and to clarify the characteristics of the presented rating scale in terms of each rating element and factor. For this study, a survey was conducted during September 11-17, 2010, and a total of 370 museum visitors participated in the survey. A sensibility rating scale used for the survey consisted of a total of 32 adjectives selected from a literature review of previous studies. To specify the dimensions of semantic space using the semantic adjectives, words with opposite meanings were analyzed with the semantic differential technique developed by Osgood et al. Using SPSS, a reliability analysis, factor analysis, and cluster analysis were conducted on the data obtained from the survey. The results of this study can be summarized as follows: According to the general public's perception of museum lobbies, five factors were found from the 19 semantic ratings of the Gyeonggido Museum of Modern Art and the 20 semantic ratings of the Seoul Museum of Art, respectively. In the case of Gyeonggido Museum of Modern Art, three additional semantic words of 'orderly', 'open', and 'original', which did not appear in the case of Seoul Museum of Art, were discovered. In the case of Seoul Museum of Art, more detailed semantic words such as 'restrained', 'ordinary', 'concrete', and 'intellectual (rational)' were obtained. Five semantic elements, which describe the two museums, were: Feelings of 'pleasantness', 'value, 'usage', 'aesthetics', and 'materials'. According to a comparative analysis of the two lobby spaces in terms of semantic rating elements, Gyeonggido Museum of Modern Art was perceived to be an orderly, original, open, soft, and female-like space, whereas Seoul Museum of Art was perceived to be aesthetic, restrained, concrete, realistic, intellectual and rational. In the coming years, the results of this study will serve as valuable data for constructing a sensibility rating scale for evaluating spatial environments of museums.