The 29 year-old passer-by, who does not wish to be named, was lucky to escape with just cuts and bruises after the 8kg rock fell from eight metres above.
Guildford Magistrates' Court heard that Majestic was working above shops on Camberley High Street on 31 May 2012 to clean stonework and install pigeon spikes.
A mobile elevating working platform (MEWP) was correctly being used for the task, but as it was being repositioned it struck a building and dislodged masonry, causing it to fall.
Nearby CCTV cameras captured the moment that the pedestrian was struck on the shoulder and fell to the ground.
The stone struck the pedestrian on the shoulder and knocked him to the ground, as dramatically captured by.
An investigation by the Health & Safety Executive (HSE) found that although barriers had been placed around the nearside support legs of the truck-mounted MEWP, there was nothing to prevent anyone from walking directly underneath the work overhead.
Magistrates were told that some of the barriers were being moved to provide a safe-working cordon further along the street where the MEWP was headed, but nobody warned the pedestrian to stand back or to be aware of the overhead work.
The incident could have been prevented had the work been better managed with a proper safety cordon in place.
Majestic Construction Ltd, of Lakeside, North Harbour, Western Road, Portsmouth, was fined £8,000 and ordered to pay £5,473 in costs after pleading guilty to a single breach of the Work at Height Regulations 2005.
After the hearing, HSE inspector Andrew Cousins said: "This was an entirely preventable incident that resulted in a large chunk of masonry being knocked onto an entirely innocent pedestrian. It is pure luck that it missed his head, otherwise he could well have been killed.
"Simply fencing off the area beneath the works and providing an alternative route around it is all that was necessary.
"Where people are working overhead in a public area they must exclude the public from the work area wherever possible. Public safety needs to be proactively managed in exactly the same way as that of those undertaking the work, and not just left to chance."
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