An image forming apparatus includes: a first rotating body pair that transports a recording medium; a second rotating body pair that transports the recording medium transported by the first rotating body pair; a first detection unit that detects the recording medium at a first position in a transporting width direction of the recording medium; a second detection unit that detects the recording medium at a second position, the second position being different from the first position in the transporting width direction; and a modification unit that modifies a shape of an image to be formed on the recording medium in accordance with a difference between a detection time during which the recording medium is detected at the first position and a detection time during which the recording medium is detected at the second position.