, T.P. Krichbaum 
,
T.J. Galama 
, A.J. Castro-Tirado 
, F. Frontera
, J. Van Paradijs , I.F. Mirabel 
,
E. Costa 
Institut de RadioAstronomie Millimétrique, 300
rue de la Piscine, F-38406 Saint Martin d'Hères, France Max Planck Institut für Radioastronomie, Auf dem
Hügel 69, D-53121,Bonn, Germany University of Amsterdam, Kruislaan 403, NL-1098 SJ Amsterdam, The
Netherlands LAEFF-INTA, Villafranca del Castillo, PO Box
50.727, E-28080 Madrid, Spain
Dipartimento di Fisica,
Università di Ferrara, Via Paradiso, 11, I-44100 Ferrara, Italy
CEA/DSM/DAPNIA Service d'Astrophysique, F-91191
Gif-sur-Yvette, France Istituto di Astrofisica Spaziale,
CNR., Via E. Fermi, 21, I-00044 Frascati, Italy
Instituto
de Astronomia y Fisica del Espacio, CC 67, Suc 28, 1428 Buenos Aires,
Argentina
Istituto TESRE, CNR, Via P. Gobetti, 101,
I-40129 Bologna, Italy 
-ray burst source GRB 970508 has been detected as a
continuum point source at 86.2 GHz with the IRAM Plateau de
Bure Interferometer (PdBI). By combining the UV tables of May 17th, 19th, 21st
and 22nd, one obtains a
point source flux of 
mJy, which amounts to a
detection. Three individual tentative detections were made
on May 19-22, and the source was only non-detected later
with 
upper limits between 0.87 and 1.83 mJy.
Observations at 232 GHz gave only upper limits. The lowest one
from combined May 19 and 21 data is 4.5 mJy ( ).
No significant variation of the source during individual observing
dates was seen in either frequency band. Comparing the
May 17-22 detection with the later non-detections, we see a significant
fading which is not well fitted with the 
law
found at higher frequencies.
We exclude that the 86.2 GHz fluxes have been modulated significantly by interstellar scintillation. This indicates that the millimetre characteristics of GRB 970508 provide a new aspect of the intrinsic development of the source.