PURPOSE: To confirm whether or not a user intends to perform a process even if the process is hard for the user by previously recording the cost for the retrieval, acquisition, and display of desired data and switching a retrieval and a display method.

CONSTITUTION: Link destination and cost information are extracted from link information of a file and stored in a link destination file name area 701 and a cost area 072 in a memory 07. Then it is judged whether the cost 072 is smaller than a cost threshold value 073 and when the cost 072 is smaller than the cost threshold value 073, the file indicated with the link destination file name 071 is retrieved and displayed by a display means 074. When the cost 072 is larger than the cost threshold value 073, on the other hand, the file of the link destination is not retrieved and a substitute display means 075 is actuated to confirm whether the user really intends to display data when the display cost for the data that the user tries to display is expensive. Consequently, a waste of retrieval can be eliminated.