The pensioner was stuck inside part of the shop in White Rock, Hastings, East Sussex, after the rear of the premises fell down at 12.27pm today.
Fire crews were involved in a "delicate operation" to release him, according to Sussex Police. The A259 road was closed while the firefighters secured the building.
The elderly man, who was not injured, had become stuck inside a part of the shop which had not been affected by the collapse.
Inspector Lee Lyons said: "Thankfully, this gentleman was in the right place at the right time as far as being in the shop was concerned.
"He was cut off by the rock fall but was able to talk to colleagues from the fire service who had to work very carefully to free him due to the risk of further collapse of the building or more rock falls.
"They were successful in doing this after a couple of hours and he emerged safe and well.
"A structural engineer has now visited the site and is concerned about the safety of four of the buildings in the area, so they are being cordoned off in order that further examination can take place.
"It is likely that there will be local disruption to traffic and pedestrians in the area while this takes place."