The aims of the present study were to investigate what kind of anxiety radiation decontamination workers have, and to analyze what factors are associated to presence or absence of their anxieties. A self-administered questionnaire was conducted, which included 10 anxiety items. A logistic regression model was then used to determine what factors were related to increased anxiety. Of 531 workers who completed the questionnaire, 477 (91.6%) complained of at least one of the 8 anxiety items. The most common anxiety item was job security (41.8%), and the least common item was working hours (6.0%). The logistic regression analysis revealed that the most common causes of related to presence of anxiety was heat illness and the most common causes of related to absence of anxiety was having someone available for consultation. The current study revealed the kinds of anxiety, and the factors associated with presence or absence of each anxiety among radiation decontamination workers. These results provide important implications for the improvement of educational content and occupational health management for radiation decontamination workers in the future.