I outline the current situation and future tasks for psychiatric services in Japanese prisons. I describe the provision of facilities specializing in psychiatric services, preparation of legal aspects related to involuntary treatment, provision of therapeutic educational programs regarding addictive crimes, and the measures required for continuation of treatment after release from prison. I also discuss how, in the current system, under the "Act on Mental Care and Treatment for Persons who have Caused Serious Cases under the Condition of Insanity," unfairness arises in the treatment of mentally disordered offenders, requiring a division between medical care and justice (correctional institutions).