As a novel biomimetic gel with spatiotemporal function, we developed “self-oscillating” gel that undergoes spontaneous cyclic swelling-deswelling changes without any on-off switching of external stimuli like a heart muscle. The self-oscillating gel was designed by utilizing the Belousov-ZhabotinskyiBZjreaction which is a oscillating reaction as a chemical model of the TCA cycle. Since the first report in 1996, we have systematically studied the novel polymer gels. As an innovative study to create a new concept of functional gels and expand the potential of gels, our studies have attracted much attention in many research fields and have inspired other related studies. Here our recent progress on the self-oscillating polymer gels was summarized.