Confidence is an important part of decision-making, yet it remains unclear at what point during a decision this confidence is computed. Previous research suggests that confidence may develop during the decision process itself and may be reflected in physiological signals such as pupil dilation. The present study examined whether pupil dilation reflects reported confidence across different stages of probabilistic decision-making. Participants completed a probabilistic reinforcement learning task while pupil size was recorded continuously using eye tracking. In each trial, participants viewed two stimuli sequentially, made a choice, and reported either high or low confidence. Mean pupil size was extracted during three predefined time windows: stimulus 1, stimulus 2, and the pre-choice period. Linear mixed-effects models were used to examine whether pupil dilation covaried with reported confidence across these stages. The results showed no significant overall main effect of confidence on pupil size. However, a significant interaction between confidence and time window indicated that the relationship between confidence and pupil dilation differed across the decision process. Contrary to expectations, this relationship was not strongest in the pre-choice window. Exploratory analyses further suggested that differences between confidence levels became more visible in later blocks of the task.  These findings suggest that pupil dilation does not reflect confidence in a simple or consistent way across probabilistic decision-making, but may instead depend on both the stage of the decision and the stage of learning.