To provide a surface mounter capable of freely moving on the floor, and an electronic component mounting line equipped with the surface mounter.

A printed wiring board conveyance device, an electronic component feeding device and an electronic component moving device for transferring electronic components from the electronic component feeding device to a printed wiring board are provided on a pedestal 3. Air-flow type heavy object supporting devices 1 are each provided on each of legs of the pedestal 3. Each of the supporting devices 1 has a leveling block 6 attached on the lower end of the leg, a boot 7 provided on the bottom surface of the leveling block 6, and an air path for discharging the air supplied into a space S in the boot 7 to the lower part of the boot 7 through an air hole 32. A recess portion 22 opening downward is formed on the lower end of the leveling block 6 and the boot 7 is fixed on an inside upper surface 22a of the recess portion 22.