It was at eleven o'clock on Friday night that the police were alerted to the accident on national highway 26 near Åled in Halmstad municipality.
Emergency services and an ambulance were also called to the scene.
According to information given to the police, the driver must have traveled in a car and driven into the bus from behind.
In addition to the driver, there were also four passengers in the bus.
All are said to be unharmed.
The driver who was seriously injured in the accident is suspected of serious drunken driving.