The laser microscopy is now an instrument indispensable for life science. Advances in molecular biology, organic chemistry, and materials science have recently enabled us to create several new classes of fluorescent probes for imaging in life science. Through combination with advances in laser microscopy and fluorescent probes, we are now able not only to image protein expression, localization, and activity state, but also to manipulate protein function in the living cell. Here, we first provide a brief introduction to fluorescent probes for cell imaging by laser microscopy and then describe methods for tagging of proteins with fluorescent probes. Finally, we summarize what biological phenomena we can image using fluorescent probes and laser microscopes.