An image processing apparatus is an image processing apparatus capable of reading a security paper document that has a ground design pattern and performing image processing, and is provided with: a second modification processing unit that visualizes a latent image included in the ground design pattern; a first modification processing unit that performs a modification process so that the latent image included in the ground design pattern is not visualized; a CPU that performs authentication regarding whether or not a user of the security paper document is an authorized user; and a CPU that performs control so that the first modification processing unit performs modification processing and the latent image is not visualized, or performs control so that the latent image is not visualized by the second modification processing unit, in the case where the user has been authenticated as an authorized user of the security paper document.