Police were called to Karlshamn's Stortorg on Saturday night to investigate an incident that is classified as a serious illegal threat.
He is suspected of having threatened a younger man with a knife, and earlier in the day had kicked down a woman in her 70s on a bicycle and threatened her with a knife.
The elderly woman suffered injuries to her legs after the attack.
The suspect will be questioned on Sunday.
The man is suspected of grossly illegal threats, assault and assault in court.