Background: The Recovery Knowledge Inventory (RKI) is one of the influential scales to assess knowledge and attitude toward recovery-oriented practices among mental health service providers. In the present study, we aimed to develop a Japanese version of RKI and examine the validity and reliability. Methods: We translated RKI into Japanese by reference to the guidelines for translating and adapting psychometric scales. A cross-sectional questionnaire survey was conducted with mental health service providers. Of a total of 475 eligible professionals, we used data from the 299 participants without missing value for the analyses (valid response rate = 62.9%). The questionnaire included Japanese RKI, Recovery Attitudes Questionnaire, The positive attitudes scale, and Japanese-language version of the Social Distance Scale. To examine the factorial validity of RKI, explanatory factor analysis and confirmatory factor analysis was employed. Convergent validity was assessed by calculating Pearson's correlation coefficients between the total RKI score and the scores for the other three scales. We also calculated Cronbach's α coefficients for the total score and for each domain of RKI to assess internal consistency reliability. Results: The participants' mean age was 40.4 years and 30.4% were men. 20-item RKI did not provide any adequate or interpretable factor solutions at any number of factors by EFAs. Thus four items (#1, 4, 5, and 13) were subsequently eliminated in stages, then 16-item RKI was employed as a consequence for further analyses. EFA with four factor structures yielded marginally interpretable constitution. Each factor represented the knowledge regarding psychiatric symptoms and recovery; knowledge about the recovery process; the understanding of what is important for recovery; and the understanding of the challenges and responsibility in recovery, respectively. Subsequent CFA suggested good fit to the data. Good convergent validity and understandable internal consistency reliability were also observed. Conclusions: The Japanese 16-item RKI revealed reasonable factorial validity, good convergent validity, and understandable internal consistency reliability among mental health professionals. Japanese cultural settings seemed to influence the four-factor structure in the present study. It can be used for future study in Japan, while future large-scale research is required to ensure robust verification.