A printer apparatus includes a first device and a second device. The first device includes a first carriage movable in a scanning direction along a guide rail and a first working device to perform a first predetermined work on an object medium. The second device includes a second carriage movable in the scanning direction along the guide rail and a second working device to perform a second predetermined work on the object medium. A first device holding mechanism is capable of holding the first device. A second device holding mechanism is capable of holding the second device. A vertically retreat mechanism is configured to move the second device holding mechanism and the second device along a vertical direction to be located below a medium supporter to support the object medium when the first working device is moved in the scanning direction to perform the first predetermined work.