An amateur photographer spotted the mammal, thought to be extinct, in early July, and passed photos to the Shropshire Wildlife Trust.
There have been numerous reports in the county, but trust mammal expert Stuart Edmunds was able to verify the image.
"There is now a possibility that they may have been living here right under our noses for a long time," he said.
Pine martens are nocturnal, house cat-sized members of the stoat and weasel family.
There is a healthy population of at least 4,000 pine martens in Scotland, and small numbers live around Snowdonia, in Wales.
The wildlife trust believes the Shropshire marten had moved across from Wales.
The first confirmed sighting of a wild pine marten in England for over a century has been recorded.