An application collaboration system for allowing a portal application executed on a Web server and a client application executed on a client terminal to collaborate with each other, the application collaboration system including: a collaboration information storage unit that stores collaboration information including information indicating an application and call information used to call a process to be executed by the application in association with information indicating a condition to extract the collaboration information; an execution location information storage unit that stores execution location information indicating an apparatus where the application is executed in association with the information indicating an application; an information extraction unit that executes a process to extract collaboration information matching said condition from said collaboration information storage unit and acquires execution location information corresponding to the information indicating an application included in the extracted collaboration information from said execution location information storage unit; and a collaboration information notification unit that notifies the apparatus indicated by the execution location information acquired by said information extraction unit of the process indicated by the extracted collaboration information.