The aim of the study was to investigate confidence in classification accuracy during category learning with three levels of categorization difficulty based on a simple logical, conjunctive or complex rule. Twenty five psychology students participated in the study. Stimuli were geometrical figures that varied on three dimensions: shape, colour, and size. We analysed differences in absolute accuracy of confidence judgments with respect to task difficulty (three levels), learning phase (early, late) and performance groups (slow and fast learners). For the simple logical task, we obtained a significant main effect of phase and a significant interaction between phase and group, suggesting that fast learners achieved higher accuracy earlier. For the conjunctive task, the significant main effect of the group showed higher accuracy of fast learners. For the complex task, there was a significant interaction between phase and group showing that judgment accuracy in slow learners did not improve during learning.