Local news agencies named the man as Tomislav Petrovic and said he had killed three immediate neighbours, a married couple and a man, in their houses, and then continued his shooting spree at the bus station.
The 41-year-old bus driver was taken to Tuzla hospital with severe injuries.
"He suffered severe gun wounds and is currently undergoing surgery but his life is not in danger," Amra Odobasic, a hospital spokeswoman, said.
Petrovic's neighbours said he had behaved strangely and suffered from depression.