He has already visited Chad and Sudan in the past week.
Ban said in Khartoum on Thursday that the peace conference, which he hopes will bring a "final settlement" to the four-year-old Darfur conflict, would take place on October 27 in Libya.
"(Gaddafi) said he will do all to bring all the leaders of the movements to participate in the meeting," Ban said.
Ban also said Gaddafi had expressed "full support" for the planned deployment of a European Union force in Chad, which borders Darfur and has been flooded with refugees in its already unstable east.
UN officials have said that Libya won out as the venue over Tanzania and other nations that had offered to host the talks because several rebel leaders have links to the north African country.
Earlier the UN chief said on his plane en route to Libya the peace effort needed the cooperation of all regional players, naming Egypt, Eritrea and Chad in addition to Libya.
Ban was met at Sirte airport by Ali Triki, Libya's minister for African affairs, who said that his country was also affected by the insecurity in Darfur.
"We are neighbours with Sudan, and we have more than three quarters of a million Darfurians working in Libya," he said.
"So the security of Darfur is very important for us, and we will work hard for success in achieving peace."
On Thursday, after meeting Omar al-Bashir, the Sudanese president, the two announced next month's resumption of peace talks between Khartoum and the rebel factions in Darfur.
After three days in Sudan, Ban visited Chad on Friday to address the humanitarian crisis caused by the Darfur war.
About 236,000 refugees have fled across the border to neighbouring Chad, according to UN agencies.
Chad and the CAR faced internal rebellions earlier this year which their governments linked to the crisis in Darfur.
The UN secretary general also visited the war-ravaged Darfur region where, according to UN estimates, about 200,000 people have died and two million more have fled their homes since 2003.
Washington has described the scorched earth policy adopted by Khartoum-backed armed groups against ethnic minority villages suspected of supporting the rebels as genocidal.
Khartoum says only 9,000 people have died in the conflict.