A treatment liquid application device for use in an inkjet printer includes an application roller to apply a treatment liquid to a recording medium before an image is formed on the recording medium, a squeeze roller disposed below the application roller and to make a pressure-contact with the application roller, a treatment liquid supply unit to supply the treatment liquid to a nip part between the application roller and the squeeze roller, and a pressure roller disposed above the application roller and to cause the recording medium to make a pressure-contact with the application roller. When the application roller applies the treatment liquid to the recording medium, a position of the application roller is not restricted in approximate load directions of the squeeze roller and the pressure roller but is restricted in directions other than the approximate load directions.