We perform the optical detection of hydrogen bubbles formed at a laser-induced microstructure on a Ni electrode during hydrogen evolution reaction, and study the dynamics of individual bubbles. Using the side-illumination technique to take both images of the bubbles and microstructure on a polished electrode we successfully correlate the bubble forming sites and surface morphology with an accuracy of ∼μm, and find that there are more than a few bubble forming sites at the periphery of the single microstructure. Interestingly, the responses of those sites to the current density are different, and as the current density increases more sites become active to form bubbles. Under the constant current operation the growth rates and formation periods of the bubbles are different at different sites within the single microstructure. These findings imply that a subtle local structure within a single microstructure greatly matters to the bubble forming activity of the sites.