An image erasing apparatus includes a stacking tray stacking the recording medium, a heater heating the recording medium to a temperature equal to or higher than the temperature at which developer on the recording medium is erased, a detector disposed downstream in a recording medium carrying direction from the heater to detect an image on the recording medium, a recording medium carrying mechanism picking up the recording medium, from the stacking tray sheet by sheet and carrying the picked-up recording medium, a storage box storing the image-erased recording medium by size, a lateral aligning mechanism disposed in the storage box so as to align the recording medium in the lateral direction, and a controller controlling the alignment operation of the lateral aligning mechanism.