A dual-purpose vacuum cleaner, wherein the dual-purpose vacuum cleaner comprises: a self-walking carriage comprising at least three wheels pivotally mounted at a bottom side thereof and rotatable on the floor, a top-opened accommodation chamber defining therein at least one bearing face, a roller brush rotatably mounted at the bottom side of said self-walking carriage and disposed at a front side relative to said accommodation chamber, a dust guide located at the bottom side of said self-walking carriage and disposed at a rear side relative to said roller brush, said dust guide having a front side thereof disposed in contact with the floor and a rear side thereof backwardly upwardly extended from said front side, a passageway having one end thereof connected to the rear side of said dust guide and an opposite end thereof connected to said top-opened accommodation chamber, and a plurality of first contacts disposed in said top-opened accommodation chamber; a first power source, a first controller and a first driver mounted in said self-walking carriage, said first controller being electrically connected to said first power source and said first contacts, said first driver being electrically connected to said first controller and coupled with at least one wheel of said at least three wheels and controllable by said first controller to rotate said at least one wheel of said at least three wheels forward or backward; a hand-held vacuum cleaner detachably accommodated in said top-opened accommodation chamber, said hand-held vacuum cleaner comprising at least one abutment face for abutting against said at least one bearing face of said self-walking carriage, a handle, a dust suction entrance located at a front side thereof and attachable to said passageway, and a plurality of second contacts for physically contacting said first contacts respectively; a second power source, a second controller and a second driver mounted in said hand-held vacuum cleaner, said second controller being electrically connected to said second power source and said second contacts, said second driver being electrically connected to said second controller and selectively controllable by said first controller or said second controller to start a vacuum cleaning function; and a cover detachably covered on said self-walking carriage to conceal said hand-held vacuum cleaner in said self-walking carriage. a self-walking carriage comprising at least three wheels pivotally mounted at a bottom side thereof and rotatable on the floor, a top-opened accommodation chamber defining therein at least one bearing face, a roller brush rotatably mounted at the bottom side of said self-walking carriage and disposed at a front side relative to said accommodation chamber, a dust guide located at the bottom side of said self-walking carriage and disposed at a rear side relative to said roller brush, said dust guide having a front side thereof disposed in contact with the floor and a rear side thereof backwardly upwardly extended from said front side, a passageway having one end thereof connected to the rear side of said dust guide and an opposite end thereof connected to said top-opened accommodation chamber, and a plurality of first contacts disposed in said top-opened accommodation chamber; a first power source, a first controller and a first driver mounted in said self-walking carriage, said first controller being electrically connected to said first power source and said first contacts, said first driver being electrically connected to said first controller and coupled with at least one wheel of said at least three wheels and controllable by said first controller to rotate said at least one wheel of said at least three wheels forward or backward; a hand-held vacuum cleaner detachably accommodated in said top-opened accommodation chamber, said hand-held vacuum cleaner comprising at least one abutment face for abutting against said at least one bearing face of said self-walking carriage, a handle, a dust suction entrance located at a front side thereof and attachable to said passageway, and a plurality of second contacts for physically contacting said first contacts respectively; a second power source, a second controller and a second driver mounted in said hand-held vacuum cleaner, said second controller being electrically connected to said second power source and said second contacts, said second driver being electrically connected to said second controller and selectively controllable by said first controller or said second controller to start a vacuum cleaning function; and a cover detachably covered on said self-walking carriage to conceal said hand-held vacuum cleaner in said self-walking carriage.