A supporting device for supporting a first article and a second article which is lower than the first article in height, comprising: a supporting member including a first positioning member (12, 16, 20) configured to position a bottom of the first article and to inhibit horizontal movement of the first article, and a second positioning member configured to position a bottom of the second article and to inhibit horizontal movement of the second article; wherein the first positioning member (12, 16, 20) and the second positioning member are both configured to position the first article and the second article respectively when lowered on the supporting member and to release the first article and the second article respectively from positioning when elevated therefrom, the supporting device further comprising: a first anti-drop member configured to advance over the first article when the first article is positioned by the first positioning member (12, 16, 20) and to prevent the first article from elevating and thereby escaping from positioning; and a second anti-drop member configured to advance over the second article when the second article is positioned by the second positioning member and to prevent the second article from elevating and thereby escaping from positioning, wherein said first positioning member (12, 16, 20) is provided at a higher position than the second positioning member is, wherein said first anti-drop member and said second anti-drop member are provided at a same side of said supporting member in plan view, wherein said first positioning member (12, 16, 20) and said second positioning member are configured to position one end of the first article that is on a side of said first anti-drop member and said second anti-drop member nearer or equally distant to said first anti-drop member and said second anti-drop member than one end of the second article that is on the side of said first anti-drop member and said second anti-drop member, and wherein said second anti-drop member is configured to retract from said one end of the first article, when said first positioning member (12, 16, 20) positions the first article. a supporting member including a first positioning member (12, 16, 20) configured to position a bottom of the first article and to inhibit horizontal movement of the first article, and a second positioning member configured to position a bottom of the second article and to inhibit horizontal movement of the second article; wherein the first positioning member (12, 16, 20) and the second positioning member are both configured to position the first article and the second article respectively when lowered on the supporting member and to release the first article and the second article respectively from positioning when elevated therefrom, the supporting device further comprising: a first anti-drop member configured to advance over the first article when the first article is positioned by the first positioning member (12, 16, 20) and to prevent the first article from elevating and thereby escaping from positioning; and a second anti-drop member configured to advance over the second article when the second article is positioned by the second positioning member and to prevent the second article from elevating and thereby escaping from positioning, a first anti-drop member configured to advance over the first article when the first article is positioned by the first positioning member (12, 16, 20) and to prevent the first article from elevating and thereby escaping from positioning; and a second anti-drop member configured to advance over the second article when the second article is positioned by the second positioning member and to prevent the second article from elevating and thereby escaping from positioning, wherein said first positioning member (12, 16, 20) is provided at a higher position than the second positioning member is, wherein said first anti-drop member and said second anti-drop member are provided at a same side of said supporting member in plan view, wherein said first positioning member (12, 16, 20) and said second positioning member are configured to position one end of the first article that is on a side of said first anti-drop member and said second anti-drop member nearer or equally distant to said first anti-drop member and said second anti-drop member than one end of the second article that is on the side of said first anti-drop member and said second anti-drop member, and wherein said second anti-drop member is configured to retract from said one end of the first article, when said first positioning member (12, 16, 20) positions the first article.