An image forming apparatus includes first, second, and third acquisition processing portions. The first acquisition processing portion acquires the potential value of a charged area, charged by the charging member, on the image-carrying member. The second acquisition processing portion acquires a state value regarding the state of a surface layer of the image-carrying member based on the potential value of the charged area acquired by the first acquisition processing portion and the current value of a charging current flowing through the charging member during formation of the charged area. The third acquisition processing portion acquires the electrical resistance value of the transfer member based on the state value acquired by the second acquisition processing portion, the voltage value of a transfer voltage applied to the transfer member, and the current value of a transfer current flowing through the charged area in response to application of the transfer voltage.