  We investigate broadband emission properties of the pulsar wind nebula (PWN)
3C 58 using a spectral energy distribution (SED) model. We attempt to match
simultaneously the broadband SED and spatial variations of X-ray emission in
the PWN. We further the model to explain a possible far-IR feature of which a
hint is recently suggested in 3C 58: a small bump at $\sim$$10^{11}$ GHz in the
PLANCK and Herschel band. While external dust emission may easily explain the
observed bump, it may be internal emission of the source implying an additional
population of particles. Although significance for the bump is not high, here
we explore possible origins of the IR bump using the emission model and find
that a population of electrons with GeV energies can explain the bump. If it is
produced in the PWN, it may provide new insights into particle acceleration and
flows in PWNe.
