The photoacoustic (PA) effect is a conversion of the light to acoustic waves due to absorption and localized thermal excitation. PA imaging possibly becomes biomedical functional imaging because optical absorption is closely associated with physiological properties, such as hemoglobin concentration and oxygen saturation. In the present study, color-dependent PA effect was examined for basis of biomedical functional imaging. US imaging clearly visualized the surface shape of the flat cable while PA imaging showed color-dependent heterogeneous reflections. The result suggests that the combination of US and PA imaging may become biomedical functional imaging when only a single wavelength of laser beam is used for PA excitation.