The study used an eye-tracking task to investigate whether preschool children with autism spectrum disorder (ASD) are able to make inferences about others' behavior in terms of their mental states in a social setting. Fifty typically developing (TD) 4- and 5-year-olds and 22 5-year-olds with ASD participated in the study, where their eye-movements were recorded as automatic responses to given situations. The results show that unlike their TD peers, children with ASD failed to exhibit eye gaze patterns that reflect their ability to infer about others' behavior by spontaneously encoding socially relevant information and attributing mental states to others. Implications of the findings were discussed in relation to the proposal that implicit/spontaneous Theory of Mind is persistently impaired in ASD.