The main purpose of this study is to analyze the patterns of internal migration in small and medium-sized cities in relation to the housing market. Examining the characteristics of migration by the county level administrative units shows that major regional cities have a relatively large proportion of internal migration that migrants do not cross the administrative boundary. In theses cities, not only the ratio of apartments to total housing is high, but housing related factors are the biggest reasons for migration. The spatial patterns of internal migration were analyzed with a focus on the housing market in case of Gangneung with high internal migration. The results are as follows. First, as intensifying internal migration with the large supply of new apartments since 2014, areas where the supply of apartments was concentrated showed high level of net in-migration, while existing areas with large populations showed high level of net out-migration. Second, analysis of OD flows revealed the dominant flows from most areas of Gangneung to areas with new apartments, and the sub-flows towards large residential areas where have suffered great net outflows. Third, there was much more movement to areas with higher housing prices than origins. This study has great implications in that it not only deals with internal migration of small and medium-sized cities that have received little attention, but also reveals that their characteristics may be different from those in metropolitan or large cities.