21世紀是網路化的資訊社會，由於個人、團體與企業在利用資訊與通訊科技的差異，使得各國數位資訊取用的能力與機會不同，有的富裕，有的貧瘠，而形成數位落差的問題。本論文旨在探討數落差的問題以及公共圖書館應擔負的任務。首先說明21世紀網路社會的來臨與知識經濟的形成；其次，闡釋數位落差的意義與內涵，並檢視國際間進行的消弭數位落差計畫；復次，探討現代公共圖書館的任務。最後總結公共圖書館在消弭數位落差扮演的角色與因應策略。

　　　　　The term '"digital divide" refers to the gap between individuals, households, businesses and geographic areas at different socio-economic levels with regard both to their opportunities to access information and communication technologies and to their use of the internet for a wide variety of activities. The article mainly discusses the problem of digital divide and public libraries' missions. Firstly, it explains what digital divide is and how to make measurement. Secondly, it explores what the missions are and roles of modern public libraries in the networked world. Thirdly, it reports some projects of bridging digital divide, which were undertaken in the United States, Great Britain and all of the world. Finally, it makes some conclusions and suggestions to public libraries in Taiwan to bridge digital divide.