To provide an image reading device which clearly reads images of a reading medium placed on a contact glass and images of a card inserted into a card slot without a focus adjustment mechanism, and an image forming device.

When the card C is inserted into the card slot 120 and then a start key 158 is pushed, card carrying rollers 104a and 104b contact with the card C. The card carrying rollers 104a and 104b carry the card C to the contact surface between a sub pressure plate 105 and a second contact glass 155. Then, the edge of the card C reaches the tapered surface of the sub pressure plate 105, and the sub pressure plate 105 is pushed away by the edge of the card to be separated from the second contact glass 155, and the card C is inserted into the contact surface between the sub pressure plate 105 and the second contact glass 155.