The group's leader, Abubakar Shekau, speaks on the video obtained by AFP for 17 minutes before showing what he said were the girls, in Muslim dress and praying in an undisclosed rural location.
A total of 276 girls were abducted on April 14 from the northeastern town of Chibok, in Borno state, which has a sizeable Christian community. Some 223 are still missing.
The footage shows about 130 girls in black and grey full-length hijabs sitting on scrubland near trees, reciting the first chapter of the Muslim holy book, the Koran, and holding their palms upwards in prayer.
There was no indication of when the video was taken, although the quality is better than on previous occasions and at one point an armed man is seen in shot with a hand-held video camera.
Also Read
Boko Haram has been waging an increasingly deadly insurgency in Nigeria's mainly Muslim north since 2009, attacking schools teaching a "Western" curriculum, churches and government targets.
Nigeria's government has been criticised for its lack of immediate response to the kidnapping but has been forced to act after Shekau threatened to sell the girls as slaves.
President Goodluck Jonathan has now accepted help from the United States, Britain, France, China and Israel, which have sent specialist teams to help in the search effort.
In the video, Shekau appears in front of a lime green canvas backdrop wearing combat fatigues and carrying an automatic weapon. Shekau does not appear in the same shot as the girls at any point during the 27-minute video.
The militant leader said that Boko Haram's brothers in arms had been held in prison for up to five years and suggested that the girls would be released if the fighters were freed.