A large number of children with developmental disorders like autism spectrum disorder (ASD), learning disabilities, and attention deficit hyperactivity disorder have high anxiety. It has also been shown that the high anxiety has harmful effects on them, directly and indirectly. In this study, we conducted a survey on community samples on the level of anxiety of children with developmental disorders in Japan that had hardly been studied so far, and compared them with the anxiety in children in a general population sample in previous studies. Analysis on the 203 participants showed that children with developmental disorders have high anxiety as compared to children as in previous studies in other countries. Particularly children with ASD had a higher anxiety compared with children with developmental disorders without ASD.