Background The stigma associated with cancer has negative impacts on cancer patients as well as the general public, who have a potential risk of cancer. To the best of our knowledge, a validated measure to assess cancer stigma among the general Japanese population does not exist. Method We translated the Cancer Stigma Scale (CASS) - a 25-item self-administered scale to evaluate stigma related to cancer - into Japanese and examined its psychometric properties. The Japanese version of CASS (J-CASS) was validated among a sample of the general Japanese population through an online survey to validate its test-retest reliability, internal consistency, and concurrent validity. Results A total of 319 responses were included in the analysis. An exploratory factor analysis eliminated two original items but showed a six-factor model (Awkwardness, Severity, Avoidance, Policy Opposition, Personal Responsibility, and Financial Discrimination), which was similar to the original scale. Cronbach's alpha for each factor was satisfactory, ranging from 0.81 to 0.91. The internal correlation coefficients were above 0.70, except for Policy Opposition. The total and subtotal scores of each factor of the J-CASS were significantly associated with respondents' age, gender, familiarity with cancer patients, and social desirability, demonstrating the scales' good concurrent validity. A substantial proportion of the participants selected unsure for some items of the scale, suggesting a further need for refining the scale. Significance of results This study demonstrated that J-CASS is a reliable and valid measure for evaluating misconceptions and stigma toward cancer in the general Japanese population.