This study aimed to quantitatively grasp the structure of support for balancing cancer treatment and work among occupational health nurses (OHNs) with the current implementation status. The anonymous questionnaire was designed based on the findings of our previous qualitative study and distributed to OHNs. The degrees of support implementation for workers with cancer, superiors and colleagues, and human resource managers were assessed for each item. Factor analysis of support items was conducted, and Wilcoxon signed-rank test was carried out to compare the support scores between the factors. Support for workers with cancer comprised six factors in which the factor, concerning the provision of information regarding resources inside and outside the company, showed the lowest score. Support for superiors and colleagues was divided into three factors, and that for human resource managers comprised two factors. By Mann-Whitney's U-test, it was found that OHNs, who worked without full-time occupational health physicians for smaller companies, showed significantly higher implementation for several support factors, such as support to human resource managers. This study revealed the structure as well as implementation status of OHNs' support for balancing cancer treatment and work, which will provide suggestions for developing training programs for OHNs to promote these activities.