In 1986, 117 municipalities in Japan had some forms of multiple-facility library system. This study reports the findings of a library use survey conducted in Kashiwa City, Chiba Prefecture, where a multiple-facility library network consisting of a central library, twelve branch libraries and two book-mobiles offers full-fledged library services to its residents. A questionnaire was circulated by mail to accroximately 3 500 residents with library registration cards representing about 5% of the total card holders. Each respondent was requested to report the name of the library he or she most often used and to state reasons for making such a selection. Card holders were then classified into four groups appording to their choice behaviour. Purposes, frequencies of use, and degrees of satisfaction were found to differ from one group to another. Branch users regard the accessibility as the important criterion for their choice, while central library users state the availability of wide selections and reference services as the basis of their choice. It is suggested that an increased mobility in recent years by motorization places emphasis relatively less on the accessibility question and more on the availability of wide-range of library services. This study was supported by a Research Grant-in-Aid provided by the Ministry of Education, Japan.