An image forming apparatus and an image forming system of the invention have: a discriminating section which discriminates necessity of a security pattern for suppressing illegal use of image creation data on the basis of a security level; a security pattern forming section which forms security pattern data on the basis of attribute data when it is determined that the security pattern is necessary; and an image forming section which forms the security pattern onto a record medium together with an image on the basis of the formed security pattern data. A consumption amount of a coloring agent which is consumed when the security pattern to suppress the illegal use of the image creation data is formed can be reduced.