Tens of thousands of troops bowed their heads in the snow outside the Kumsusan Memorial Palace, where the late strongman's body had lain in state in a glass coffin, as heir Kim Jong-Un led the cortege, state television showed.
A limousine bearing a huge portrait of a smiling Kim Jong-Il was at the front of the funeral convoy, which began moving slowly from the palace in Pyongyang on icy roads.
Jong-Un was dressed in black, bare-headed and gloveless despite the cold, holding to the side of his father's hearse. He was accompanied by top military and civilian officials -- including his influential uncle Jang Song-Thaek.
State television earlier broadcast undated scenes of mass grief at the memorial palace, with Kim Jong-Un consoling mourners and bowing deeply to his father's coffin. Thousands of citizens were expected to line the streets.
Amid mourning music, the TV also carried file footage on the life of the "Dear Leader", who held absolute power for 17 years in the nuclear-armed nation and presided over a famine that killed hundreds of thousands.
"The people bid farewell to father General in great sorrow," said the main headline in ruling party newspaper Rodong Sinmun.
"The most heartbreaking time has come, when we cannot but bid farewell to the great father everyone in this land had followed with their hearts and souls."