An image forming apparatus includes an image bearing member; a transfer member configured to form a transfer portion where the toner image is transferred from the image bearing member by being supplied with a transfer bias; a carrier liquid supplying portion configured to supply the carrier liquid to the transfer portion; a transfer bias voltage source capable of applying the transfer bias to the transfer portion; a detecting portion configured to detect at least one of a voltage and a current at the transfer portion; and a setting portion configured to set the transfer bias during non-image-formation on the basis of a detection result of the detecting portion when a setting bias is applied from the transfer member in a state in which the carrier liquid is in the transfer portion.