An image forming apparatus includes a controller configured to execute: a task that measures a plurality of first color patterns; a task that, on the basis of a first output value corresponding to a measurement result of the first color patterns, determines a threshold value; a measurement task that measures a plurality of second color patterns; and a task that detects an amount of color misregistration on the basis of a result of a comparator comparing a second output value corresponding to a measurement result of the second color patterns with a threshold value corresponding to each of the second color patterns. In the measurement task, the controller controls whether or not to set the threshold value to the threshold value corresponding to each of the second color patterns on the basis of the first output value.