An information processing apparatus (2000) includes a recognizer (2020). An image (10) is input to the recognizer (2020). The recognizer (2020) outputs, for a crowd included in the input image (10), a label (30) describing a type of the crowd and structure information (40) describing a structure of the crowd. The structure information (40) indicates a location and a direction of an object included in the crowd. The information processing apparatus (2000) acquires training data (50) which includes a training image (52), a training label (54), and training structure information (56). The information processing apparatus (2000) performs training of the recognizer (2020) using the label (30) and the structure information (40), which are acquired by inputting the training image (52) with respect to the recognizer (2020, and the training label (54) and the training structure information (56).