It is often said that Japanese traditional institutionalism in labor studies(JTILS) isn't necessarily useful for analyzing current problems, like inequality and poverty among workers. This kind of obsoleteness in JTILS is caused by two blind sides: inattention to the renewal of the theory about institution and the breaking off the relation with welfare studies. In order to conquer this weakness, the theory about institution of employment and its evolution in the 20th century is reconsidered, and besides, the ground for nexus of employment and welfare is shown in this paper. On the basis of this reconsideration, I discuss three problems which Japanese workers are currently confronted with and provide four hypothetical propositions: (1) Institution of employment itself is still robust in the 21th century. (2)Employment system of the last century is changing, and can be transformed flexibly.(3)The new employment system will not be legitimated without overcoming the negative side to the old employment system. (4)For JTILS, the cooperation with welfare studies is indispensable to analyze current labor problems. Lastly, I briefly address some research agenda.