An image forming apparatus includes a first container to accommodate liquid developer for replenishment to a developing container, and a second container to accommodate carrier fluid containing a charge control agent for replenishment to the first container. The concentration of the charge control agent in the carrier fluid accommodated in the second container is between equal to or more than 10 wt % and equal to or less than 20 wt %. A driving unit is driven so as to replenish the charge control agent accommodated in the second container to the first container, and a control unit controls the driving unit based on image coverage of an output image so that a concentration of the charge control agent in the liquid developer accommodated in the first container becomes a predetermined value.