A driving device to be used in an image forming apparatus includes an input gear; a partly non-toothed gear having a toothed portion engageable with the input gear and having a non-toothed portion; a holding member capable of placing the partly non-toothed gear in a holding state in which the non-toothed portion opposes the input gear and the partly non-toothed gear is not engaged with the input gear and capable of placing the partly non-toothed gear in a released state in which the holding state is released; a cylindrical member rotatable by receiving a rotational force; and an entering portion which is rotatable together with the partly non-toothed gear and which is capable of entering an inside of the cylindrical member and capable of receiving the rotational force from the cylindrical member by a frictional force between the entering portion and the cylindrical member.