  The Infrared Space Observatory observed the field of the $\gamma$--ray burst
GRB 970508 with the CAM and PHT instruments on May 21 and 24, 1997 and with PHT
in three filters in November 1997. A source at 60 $\mu$m (flux in May of $66\pm
10$ mJy) was detected near the position of the host galaxy of this
$\gamma$--ray burst. The source was detected again in November 1997, at a
marginally lower flux ($43\pm 13$ mJy). A Galactic cirrus origin and a stellar
origin for the emission can be ruled out on the basis of the infrared colours.
The marginal evidence for variability in the 60 $\mu$m flux between May and
November is not sufficient to warrant interpretation of the source as transient
fireball emission. However, the infrared colours are physically reasonable if
attributed to conventional dust emission from a single blackbody source. The
probability of detecting a 60 $\mu$m by chance in a PHT beam down to a
detection limit of 50 mJy is $\sim 5\times 10^{-3}$. If the source is at the
redshift of the host galaxy of the $\gamma$--ray burst the fluxes and upper
limits at wavelengths from 12 $\mu$m to 170 $\mu$m indicate it is an
ultraluminous infrared galaxy (L$_{\rm ir} \sim 2\times 10^{12}$ L$_{\sun}$).
The star formation rate is estimated to be several hundred solar masses per
year, depending significantly on model-dependent parameters. If this source is
associated with the host galaxy of GRB 970508, progenitor models which
associate GRBs with star-forming regions are favoured.
