Hell and the Lake of Fire are two separate things.
Hell is the holding place for the souls of people (such as the rich man in Luke 16: 19 - 23) that rejected the message for their age.
Revelation 20: 14 - 15: And death and hell were cast into the lake of fire. This is the second death. And whosoever was not found written in the book of life was cast into the lake of fire.
The souls in Hell will be cast into the Lake of Fire after the Great White Throne of Judgment.
Hell itself after having been emptied out of its subjects (at the general resurrection for the Great White Throne of Judgment) will lastly be cast into the Lake of Fire.