The contemporary tendences emphasize the use of so-called inquiry-based learning (IBL). However, there remains a question-by which ways should be the active inquiry of pupils induced? The author of this article finds the answer in the union of the theory learning tasks and theory of the inquiry-based instruction. Via the analytical and comparative approaches, it turns out that two categories of the inquiry tasks can be used. The first one was provisionally marked as "instructive inquiry tasks", the second one as "inquiry tasks with internal activation". Both stated tasks have different essence in how are the pupils induced to perform the inquiry learning activities.