A detecting device for detecting the presence or absence of a sheet contained in a sheet containing portion includes a rotatable arm portion brought into contact with the sheet contained in the sheet containing portion, a stopper portion rotatable in association with the arm portion for determining the position of the arm portion when there is no sheet in the sheet containing portion and whose rotation is regulated when there is no sheet in the sheet containing portion. And when the sheet in a conveying path is to be pulled out, the arm portion is retreated from a position determined by the stopper portion due to the pressure of the sheet being pulled out.