Abstract
In the conventional information retrieval research, evaluation of information retrieval system has been performed mainly on the basis of precision and recall of final research result. However, modern retrieval systems are designed to provide results through the interaction with users. The decision by a user to stop his search is therefore influenced by the interactions done up to the point. The survey by questionnaires was conducted to clarify the factors which affect the decision of stopping a search. In the case when users stop search in unsatisfied way, many non-essential reasons are pointed out for giving up further search. The implications of the stop of a search in user behavior study are emphasized.