Judge Maree Mackenzie said she was amazed by the incident.
"I must say it is nothing but bully boy behaviour."
The baton incident happened at the Pukuatua St bus stop on October 31 last year.
Brown was opening and closing and waving around the baton, which he had bought the day before. A member of the public called police.
Brown's lawyer on that charge, Rob Vigor-Brown, said his client was a "good young man" who seemed to have got on the wrong track.
Mr Vigor-Brown questioned why Rotorua shops sold the batons, which he said were prima facie offensive weapons.
"It shouldn't have been sold to him in the first place," he said.
Judge Mackenzie said while that was "interesting logic" the better question was why Brown bought it.
The judge noted Brown had been in custody since December so the sentence would in effect be time served, or close to it. She also made an order for destruction of the baton.