  Motivated by recent observations which detect dust at large galactocentric
distances in the disks of spiral galaxies, we propose a mechanism of outward
radial transport of dust by spiral stellar density waves. We consider spiral
galaxies in which most of dust formation is localized inside the corotation
radius. We show that in the disks of such spiral galaxies, the dust grains can
travel over radial distances that exceed the corotation radius by roughly 25%.
A fraction of the dust grains can be trapped on kidney-shaped stable orbits
between the stellar spiral arms and thus can escape the destructive effect of
supernova explosions. These grains form diffuse dusty spiral arms, which
stretch 4-5 kpc from the sites of active star formation. About 10% of dust by
mass injected inside corotation, can be transported over radial distances 3-4
kpc during approximately 1.0 Gyr. This is roughly an order of magnitude more
efficient than can be provided by the turbulent motions.
