A veto by one of the five permanent members -- Britain, China, France, Russia and the United States -- would have doomed his chances.
The poll is not binding on the UN but puts Ban Ki-Moon on course to takeover from the current Secretary-General, Kofi Annan.
Mr Annan’s 10 year term in office ends on December 31.
The formal vote will be held next Monday and the Security Council will then relay its choice to the General Assembly for endorsement.
Under the UN Charter, the secretary general is elected by the 192-member General Assembly on recommendation of the Security Council.
Crucial poll
The important informal poll was the first to differentiate ballot sheets used by the council's 10 non-permanent members from the five permanent members.
62 year old Ban Ki-Moon has won all four of the UN Security Council’s informal polls despite concern in some quarters that a higher profile candidate is needed.
Qatar’s UN Ambassador, Nasser al-Nasser, said 14 of the Council's 15 members voted in favour of Ban.
The the 15th member cast a "no opinion" vote.
India's candidate, UN under-secretary general Shashi Tharoor, finished second to Ban.
He has offered his warmest congratulations to the winner.
"It is clear that he (Ban) will be our next secretary general," Tharoor
said.
"I wish Mr Ban every success in that task. I will strongly support him."
US buoyed
Based on the results, US Ambassador to the UN John Bolton has urged the 15-member council to decide "as soon as possible, this week hopefully" when to schedule a formal vote.
"It was sufficiently clear that all members of the council agreed we would move to a formal vote on Monday," Bolton said.
"The United States is very pleased with the outcome."
The US is pushing for a world class administrator and hope Mr Ban will fill that role.
Mr Bolton said he "would be surprised' if new candidates were to throw their hats into the ring at this late stage.
Geographic rotation
There is a broad consensus in the world body that an Asian must lead the organization in line with an unwritten rule of geographic rotation.
An Asian has not held the post since U Thant, a Burmese, served from 1961-71.
Last week, a confident Ban traveled to New York to lobby for public support and laid out his vision for a revamped world body in the 21st century.
In an interview with AFP from Seoul Monday, he reiterated that the most urgent issue confronting the UN was "management reform, regaining the trust and confidence of member states and major stakeholders."
He said UN activities were overstretched because of the ineffective
delivery of some services. "We need to consolidate, coordinate, reduce the overlap between agencies... We need to promise less and deliver more."