An image-forming-apparatus simulation apparatus includes a storing section, a first acquiring section, a generating section, a display section and a control section. The storing section stores a defective event table. In the defective event table, event specifying information are associated with image correction rules. Each event specifying information represents a defective event relating to an image forming apparatus. Each image correction rule represents a method for simulating an influence of a defective event on an image formed by the image forming apparatus. The generating section selects at least one image correction rule. The generating unit executes image processing on target image data based on the selected image correction rule to generate defect-image data representing a defect image expected to be formed on a recording medium when the defective event occurs.