An image processing apparatus includes a first detection unit that executes first detection processing for detecting an object presumed to be a human from an image by using a trained model relating to humans, a second detection unit that executes second detection processing for detecting an object presumed to be a human from the image at least by using pattern matching, a determination unit that determines whether the object detected through the first detection processing corresponds to the object detected through the second detection processing, a correction unit that corrects a detection result relating to the object that is detected through the first detection processing and is determined to correspond to the object detected through the second detection processing, and a calculation unit that calculates the number of humans in the image based at least the detection result corrected by the correction unit.