Hesse's interior minister Peter Beuth told DPA that the man was shot dead in a struggle with police after he took hostages inside a cinema in Viernheim western Germany on Thursday afternoon.
No patrons of the cinema complex were injured and all have been released, Beuth told AFP.
Police from nearby Darmstadt said there is no evidence of an Islamist background behind the attack.
Security officials also told DPA that they do not currently suspect that there was a terrorist motive, and that the man was psychologically disturbed.
Police said they were still investigating whether the man's gun was actually lethal or was firing blanks. Unconfirmed reports from Bild tabloid said that police had also found what appeared to be a hand grenade and explosives vest next to the man's body after he was killed and these items were under investigation.
But a reporter for Deutsche Welle wrote on Twitter that police and prosecutors said to "leave [them] alone with rumors about explosive belt" and would not give a confirmation.
The man barricaded himself inside the building with hostages.
The cinema stormed by the man in Viernheim. Photo: DPA.
Special police forces flew in from Frankfurt on a helicopter, overpowered the man and shot him dead.
"The assailant moved through the cinema complex, according to the information we have now, and appeared confused," Beuth said.
"There were hostages inside and there was a struggle [with police} until in the end he was dead."
Beuth added: "We have no information that anyone [among the cinema-goers] was injured."
Cinema employees have told the Mannheimer Morgen that there were 15 people in the cinema room which the man entered. Among them were some children.
Initial reports had referred to dozens of wounded people and several shots fired, but these were later refuted by authorities.
Later accounts said that several people had been hurt by tear gas during the police raid but this was also denied.
A police spokeswoman in the nearby city of Darmstadt confirmed that "all the hostages were unhurt and led out of the building".
Some witnesses told German media that they had seen the man enter with "an ammunition belt" draped over his shoulder.
"I saw that something was happening. I called the police and told them to come immediately," the cinema manager told Bild daily without giving her name.
It is not yet confirmed how many people were inside the cinema, but a Darmstadt police spokesperson told DPA that they were operating under the assumption that the theatre was not full.
Another police spokeswoman told AFP they were investigating what type of weapon the assailant used, adding that it was possible it fired blanks.
Viernheim is just northeast of Mannheim in south Hesse. Google Maps