Comfortable environment is necessary for human-friendly urban space with small stresses. Riverine areas have a potential ability to provide comfortable exterior space with the existence of water surface. In this paper, physical and sensational factors relevant to comfort sensation are analyzed on the basis of field observations of visual, sound and thermal environment as well as questionnaires on various human sensations in riverine areas. Applying the quantification theory, we revealed the influence of various sensations on comfort, resulting in the significance of sound and thermal environment as well as visual environment.