The total and segmental microphotoelectric plethysmographs (-m; MPPG) were developed by using CdS photoconductive cells and rabbit ear chambers. The former were obtained from a whole microcirculatory unit and the latter from segmental vessels in the microcirculation of which images were projected on a focusing glass. Both record the dynamic behaviors of the microcirculation continuously and quantitatively, and permit microscopic observations. The total and segmental MPPGs reflect various fluctuations of vasomotion and of blood flow in the microcirculation. In the microcirculatory blood flow, rhythmic fluctuations of 4-8, 8-12, and 0.5 or fewer counts/min were distinctly noticed in addition to the basic rhythm of 1-3 counts/min.