要旨：This paper theoretically investigates the relationship between costs for telework and the location of firms and households in a city. I extend the model of Ogawa and Fujita (1980) by introducing two types of companies with different technologies; one is teleworking company hiring more teleworkers and the other is an office company hiring more on-site workers. Only on-site workers conduct face-to-face communication with other firms and incur communication costs.  This paper shows that (i) when telework cost decreases, the first teleworking companies appear in either of two candidate locations: the edge of the existing central business districts (called CBD fringe) or the edge of the residential districts (called urban fringe). If face-to-face communication cost is high, and commuting cost and the ratio of labor input for teleworkers in telework companies are low, then the first telework company is located at the CBD fringe;  otherwise at the urban fringe. (ii) When the telework cost further decreases, the number of telework companies, wage, and welfare increase. In contrast, bid rent and city boundaries decrease. Former empirical researches showed different evidence for the location of primary telework companies; one is nearby CBD and the other is in the suburban area. However, this is the first paper to demonstrate both results in a model and to show the difference depends on the several key parameters: face-to-face communication cost, commuting cost, and the ratio of labor input for teleworkers in telework companies.