According to Japanese broadcaster NHK, citing a defense ministry source in Tokyo, the rocket flew for 120 km (75 miles) and then broke up into four pieces, crashing into waters off the west coast of the Korean peninsula.
DPRK said it wanted the Unha-3 rocket to put a weather satellite into orbit.
The rocket's flight was set to take it over a sea separating the Korean peninsula from China, with an eventual launch of a third stage of the rocket in seas near the Philippines that would have put the satellite into orbit.
The Unha-3 rocket took off from a new launch site on the west coast of DPRK, near the Chinese border.
The launch had been timed to coincide with the 100th birthday celebrations of the country’s founder, Kim Il-sung.