A portable electronic device (100, 100A, 100B), comprising: a first body, having a bottom surface and an opening located at the bottom surface; a second body, pivoted to the first body, having a rear surface and a magnetic part located at the rear surface; and a supporting mechanism (130, 130a, 130b), disposed in the first body corresponding to the opening, wherein the supporting mechanism (130, 130a, 130b) comprises a support shaft, the support shaft has a first end part and a second end part opposite to the first end part, and a magnetic element, the supporting mechanism characterised by further comprising: a positioning stand, the positioning stand has a slide rail and a plurality of positioning protrusions, the positioning protrusions are arranged at intervals in the slide rail, the first end part is slidably disposed in the slide rail, and the magnetic element is pivoted to the second end part, wherein the rear surface of the second body is rotated toward the bottom surface of the first body to allow the magnetic element to be magnetically attracted to the magnetic part, the rear surface of the second body is then rotated away from the bottom surface of the first body, the magnetic element and the support shaft are driven by the second body to move out from the first body via the opening, and when the first end part of the support shaft that slides in the slide rail is engaged with any one of the positioning protrusions, the support shaft supports the second body. a first body, having a bottom surface and an opening located at the bottom surface; a second body, pivoted to the first body, having a rear surface and a magnetic part located at the rear surface; and a supporting mechanism (130, 130a, 130b), disposed in the first body corresponding to the opening, wherein the supporting mechanism (130, 130a, 130b) comprises a support shaft, the support shaft has a first end part and a second end part opposite to the first end part, and a magnetic element, the supporting mechanism characterised by further comprising: a positioning stand, the positioning stand has a slide rail and a plurality of positioning protrusions, the positioning protrusions are arranged at intervals in the slide rail, the first end part is slidably disposed in the slide rail, and the magnetic element is pivoted to the second end part, wherein the rear surface of the second body is rotated toward the bottom surface of the first body to allow the magnetic element to be magnetically attracted to the magnetic part, the rear surface of the second body is then rotated away from the bottom surface of the first body, the magnetic element and the support shaft are driven by the second body to move out from the first body via the opening, and when the first end part of the support shaft that slides in the slide rail is engaged with any one of the positioning protrusions, the support shaft supports the second body. a positioning stand, the positioning stand has a slide rail and a plurality of positioning protrusions, the positioning protrusions are arranged at intervals in the slide rail, the first end part is slidably disposed in the slide rail, and the magnetic element is pivoted to the second end part, wherein the rear surface of the second body is rotated toward the bottom surface of the first body to allow the magnetic element to be magnetically attracted to the magnetic part, the rear surface of the second body is then rotated away from the bottom surface of the first body, the magnetic element and the support shaft are driven by the second body to move out from the first body via the opening, and when the first end part of the support shaft that slides in the slide rail is engaged with any one of the positioning protrusions, the support shaft supports the second body.