Around 100 people were living in the Chojuen facility at the time of the disaster, but damage to the building and the water outage made it difficult for the staff to maintain a sanitary environment.
The facility found alternative accommodation for most of its residents and moved them, some by helicopter. At one point, only eight residents remained.
When electricity and water were restored last month, the facility began welcoming people back. By April 15, it had 37 residents.
On April 16, the facility's courtesy car pulled up to the entrance with two more returnees, including Kobayashi Fusa, 86, who said she was just happy to be back after weeks living in another city.
"The home is warm, and I feel relieved that I've finally come home," she said. "I want to spend my time with everyone as before."
Facility director Nakamura Mitsuhiro said, "At the time of the earthquake, there was no electricity and no water supply, so we asked the residents to evacuate. I am very happy to see them back in good health today, and I feel a sense of 'welcome back' and 'thank goodness.' We will continue to care for their health so their lives can get back to normal."