In Japan, amidst insufficient legal provisions and governmental support, in 2010, the first rape crisis center, the Sexual Assault Crisis Healing Intervention Center Osaka (SACHICO) was established. We compared SACHICO visitor data from 2010 to 2021 with National Police Agency statistics to clarify the current situation of sexual assault victims in Japan and considered future issues for Japan to address. This study was a cross-sectional study that analyzed the data described below. All visitations to SACHICO between April 2010 and December 2021 were considered targets for data totaling. Data on crime statistics were gathered from the official governmental statistics portal site. A total of 12 036 visitations occurred, of which 3189 were first-time consultations; 3100 initial medical examinations were conducted, and no medical examination was conducted in the remaining 89 cases (2.7%). The number of initial medical examinations increased 3.7 times from 2010 to 2021. Victims under the age of 19 comprised 60% of the total number of initial medical examinations (1863/3100). The reporting rate for all 3100 initial medical examinations was only 31.3% (969/3100) of the cases. The proportion of forcible sexual intercourse versus forcible indecency were the converse of those observed among acknowledged cases nationwide and in Osaka Prefecture. For several years, the number of initial medical consultations at SACHICO has exceeded that of acknowledged cases in Osaka Prefecture. Support for victims of sexual assault in Japan is still insufficient. It is necessary to strengthen the system of rape crisis centers system to realize an unbroken chain of support for victims.