The observed sea level (SL) around the Japanese coast shows a peculiar multidecadal variation with the peak in the 1950s followed by the gradual fall until the 1970s and the rebound continuing to the present, making the recent SL rise less remarkable in the historical record. An ensemble mean of the historical simulations conducted for the Coupled Model Intercomparison Project phase 6 (CMIP6) using the Meteorological Research Institute Earth System Model version 2.0 (MRI-ESM2.0) reproduces this variability well, implying that this was a forced one. The MRI-ESM2.0 simulations for the Detection and Attribution Model Intercomparison Project suggest that the increase in anthropogenic aerosols caused the SL fall from the 1950s to the 1970s and the increase in greenhouse gases caused the SL rise after that. Additional sensitivity runs indicate that the surface heat loss in the North Pacific due to anthropogenic aerosols plays a dominant role in the SL fall.