The council voted 15-0 to back the US-drafted sanctions resolution banning exports of coal, lead and seafood.
Pyongyang has claimed to have developed a hydrogen bomb and has continuously threatened to strike the US.
North Korea is already under UN sanctions to force the leadership to curtail its weapons programmes.
The new sanctions were agreed on Monday after the US removed some of the tougher proposals it had announced last week, including a complete oil embargo and measures to freeze the assets of North Korean leader Kim Jong-un.
