Disclosed are an image forming optical element, an image forming optical array, and an image reading device. The invention is to provide a technique in which high precision positioning is not necessary with a simple configuration to form an erected image of an object. The image forming optical element is provided with an incident unit having a first lens face to which a light beam output from an original document (object) is input, an output unit having a second lens face outputting the light beam, and a bent unit connecting the incident unit and the output unit at an angle are integrally formed into a transparent medium. The bent unit has a reflection face reflecting the incident light beam input to the first lens face and guiding the light beam to the second lens face. The incident light beam is collected at any of the incident unit, the bent unit, and the output unit to form an intermediate image of the object, and the intermediate image is formed on the output side of the second lens face to form an erection image of the object.