It was at 4 pm that the police were alerted to the accommodation in Katrineholm.
The missing 85-year-old is described as forgetful due to his illness.
During the day, the police searched for the man who has a long white beard and was wearing a red jacket when he disappeared.
The man must also have used a gray walker.
If anyone has made any observations, the police want to find out.
"Stay with him until the police arrive at the scene," the police write on their website.