One of the main aims with respect to the evolution of spiral galaxies is to clarify how the disk and bulge were formed. The study of bulges has usually been focused on how bulges resemble to elliptical galaxies. For the study of the evolution of elliptical galaxies, the color-magnitude relation (C-M relation) gives us a clue to understanding the formation and evolution of ellipticals. In fact, the tight C-M relation of ellipticals (Bower et al. 1992) was interpreted as the sequence of the metallicity difference (Kodama and Arimoto 1997). On the contrary, there are few observations for the C-M relation of bulges. On the analogy of elliptical galaxies, the C-M relation of bulges, if it exists, may be one of the most important clues to understanding the formation process of bulges. The main goal of the present study is to investigate the C-M relation of bulges.