This paper seeks to review the gentrification studies in the Western countries, and obtain implications for Japanese cities.The article begins with a review of the literature concerned with social effects of gentrification. In the capitalist countries, at the outset, many people expect that gentrification is caused by private ecnomy. However the effects of gentrification are not so expected for the several reasons. One reason is that most of inmovers to the gentrified neighborhoods are not part of a ‘back to the city movement’, but ‘staying in the city’. The other is that gentrifiers revitalizing abandoned areas are limited in number. On the contrary, it causes the displacement of the socioeconomically weak. Most of them are low income, elderly and minority. They feel the sting of the displacement caused by urban revitalization. Furthermore it results in producing a lot of homeless people.The third chapter treats with five theoretical issues, which are institutions, stage models, rent-gap theory, the new middle class, and marginal gentrifiers. According to the institutionalist approach, central and local government, estate agents, and building societies, are the inducers of gentrification. The stage model explains the gentrification process positively by inmovers' attitude to accept risks in the deteriorated areas. Rent-gap theory explains gentrification structurally by the movement of capital, back to the inner city. The new middle class is on the rise due to industrial restructuring.They prefer to live near the city center, so they cause gentrification. They prefer not only historical architecture, but also modern amenities. Inmovers to the gentrified neighborhoods, are not only the new middle class. There is also the formation of reproducing marginal gentrifiers. Marginal gentrifiers come to live in the inner city because of alternative life-styles. Many researchers agree that no approach cannot explain the phenomenon alone, and some of them seek to integrate several approaches.In section four I argue the applicability of researches on social effects and theoretical approaches in Western countries for Japanese cases. First I show two bases for the occurrence of gentrification in Japanese cities. One is the recent trend of upgrading living spaces. Most Japanese houses are built of wood, so they become obsolete without maintenance. It is easy to scrap obsolete houses and renovate new ones. Recently there are many cases of rehabilitating modern Western-style buildings and reforming the living layout of condominiums. The other is the restructuring of the inner city. In the 1970s most central cities lost affluent people. Many heavy industries scattered from metropolitan regions to nonmetropolitan areas. Although the inner city area in the central cities lost population, it also provides opportunities to increase population again. Actually recurrence of population appeared in some of those large cities during the late 1980s. I argue that three primary factors may cause gentrification in Japanese cities. The first one is industrial restructuring. Industrial restructuring produces new professionals. They may be potential gentrifiers. The second one is suburbanization. Expanding urban regions make a long commute to the office in the central city. So many people prefer to live not so far from the office. The third one is the supply of condominiums. Many people invested in them during the late 1980s, because of lower interest rates. Most of them located in the inner city and induce inmovers.Second, I discuss future directions for research on gentrification in Japanese cities. There may be three main issues. The first one is resettlement in the inner city. Municipal officials of most large central cities are working to prevent the population from decreasing.