South Korea's defense ministry said the missile flew about 60km (40 miles), according to the BBC.
It is the latest in a series of tests which the North says is peaceful but is widely believed to be part of a program to develop nuclear weapons.
The launch comes on the eve of a visit by China's President Xi Jinping to the U.S. to meet President Donald Trump.
The two will discuss how to rein in North Korea's nuclear and missile programs.
The North is banned from any missile or nuclear tests by the UN, though has repeatedly broken those sanctions.
U.S. Secretary of State Rex Tillerson described the launch as "yet another" intermediate range ballistic missile, adding: "The United States has spoken enough about North Korea. We have no further comment."
Read alsoNorth Korea maintains readiness for nuclear test at any time: South Korea – ReutersThe U.S. military's Pacific Command said it appeared to have been a KN-15 medium-range ballistic missile.
"The North American Aerospace Defense Command (Norad) determined the missile launch from North Korea did not pose a threat to North America," it said.
Japan called the launch "provocative", while South Korea condemned it as "a blunt challenge" to the UN and "a threat to the peace and safety of the international community as well as the Korean peninsula".
Last month, North Korea fired four ballistic missiles towards the Sea of Japan from the Tongchang-ri region, near the border with China.
Japanese PM Shinzo Abe called it a "new stage of threat".
Last week, the U.S. Treasury slapped sanctions on 11 North Korean business representatives and one company.
On Tuesday, U.S. politicians overwhelmingly backed a bill relisting the North as a state sponsor of terror.
North Korea responded by warning that it will retaliate if the international community steps up sanctions, saying the U.S. was forcing the situation "to the brink of war".
Donald Trump warned in a recent interview that the U.S. is willing to tackle North Korea alone if China does not help rein its troublesome neighbor in.
China has long been North Korea's closest diplomatic ally and trading partner, but the relationship has become increasingly strained over Pyongyang's refusal to halt nuclear and missile testing.