Abstract: The 2023 Nobel Prize in Physics has been awarded to three scientists in the fields of ultrafast laser science and attosecond physics for their outstanding contributions to the generation and application of attosecond light pulses. Their work has made it possible to study the ultrafast electron dynamics inside atoms, opening the door to the world of electrons. Attosecond spectroscopy is now an important research tool in many fields such as physics, chemistry, and biology. In this paper, we will briefly introduce the historical background of the attosecond light pulse, methods for its generation, and its applications in probing ultrafast electron dynamics.