Background: Circumscribed interests (CIs) are regarded as one of the common symptoms for individuals with autism spectrum disorder (ASD). Although some studies have found attentional bias toward CI-related stimuli for individuals with ASD, few studies have directly explored the reasons for these findings. Method: Children with ASD (n = 15) and age-matched typically developing (TD) children (n = 15) completed a Stroop-like task and a modified dot-probe task, and their reaction times were measured. The stimuli of these tasks included neutral objects and objects related to CI for individuals with ASD. Results: Children with ASD had longer reaction times to name colors of CI-related stimuli than neutral stimuli in the Stroop-like task. Similarly, in the modified dot-probe task, if the CI-related stimulus was presented simultaneously with the neutral stimulus, children with ASD responded faster to the target that appeared in the previous location of the CI-related stimulus (i.e. congruent condition) than to the neutral stimulus (i.e. incongruent condition). Importantly, the reaction times of children with ASD in the incongruent condition were significantly slower than in the baseline condition, where both neutral stimuli were displayed simultaneously with stimulus-onset asynchrony (SOA) of 500 ms. In contrast, there was no significant difference in reaction times to CI-related stimuli and neutral stimuli in both tasks for TD children. Conclusions: These findings suggest children with ASD have attentional bias toward CI-related stimuli, because of difficulty disengaging attention from CI-related stimuli with SOA of 500 ms.