An image forming apparatus that forms an image on a recording sheet by discharging ink droplets from nozzles provided in a print head on the recording sheet includes: a light emitting unit that generates detection light intersecting a discharge path of the ink droplets; a discharge signal output unit that outputs a discharge signal used to discharge the ink droplets from a detection target nozzle; a first light receiving unit that receives scattered light generated by irradiating the ink droplets with the detection light and outputs a first detection signal; a second light receiving unit that receives the detection light having passed through the discharge path of the ink droplets without irradiating the ink droplets and outputs a second detection signal; a determination unit that determines whether the detection target nozzle is a defective nozzle; and a correction unit that corrects a determination result of the determination unit.