Three of the victims in the attack on a village near the town of Bosso, on the border with Nigeria, were shot dead while the two others were burned to death, the radio reported, blaming Nigeria-based Boko Haram jihadists.
The militants burned more than 100 homes and 100 motorcycles, as well as the central market, the report added.
Anfani private radio also carried reports of the attack and said the insurgents "came on horseback".
The attack is the second of its kind in a week along Niger's south-east border with Nigeria, where troops from Niger and neighbouring Chad have been battling the Islamists for months.
On June 18, Boko Haram killed 38 people, mostly women and children, in an attack on two villages in the same area.
Niger announced on Wednesday that its forces had killed 15 militants in ground and aerial operations between June 18 and 23.