The present study is an attempt to clarify effective use of handheld electronic dictionaries (hereafter ED) for language learning in Japanese EFL context. For this purpose, we examined EFL learners' look-up behavior with ED through the think-aloud technique, and found some strategies for efficient use of ED, particularly by analyzing look-up behavior Five postgraduate students of a graduate school took part in the study as good language learners (hereafter GLLs). To compare their look-up behavior with that of false beginners (hereafter FBs), five college students also participated. The experiment was conducted with one participant at a time on an appointment basis. No time constraint and no limit on the number of target words to be looked up were set in the experiment. After transcribing their verbal descriptions, some strategies for effective ED use were extracted. The analysis of the qualitative data suggested the possibility that the ED's functions had provided not only GLLs but also FBs with scaffolding for EFL learning. Also, the results revealed that GLLs were good ED users.