Alexander Singerman, 31, was last seen leaving his work in Auchencruive heading to a meeting at the Gaiety Theatre in Ayr on Wednesday, May 10.
However, he never arrived at his destination.
His car, a white Volkswagen Polo, was found near his work and he was seen walking towards St Quivox, near to the Agricultural College on the B743.
Alexander is described as 6ft in height, with short black hair and has a sallow complexion.
He was last seen wearing a red and black checked lumber-style jacket.
Chief Inspector, Annette Morrison, said: “Officers are continuing their search for Alexander and are carrying out door to door enquiries and speaking to family and friends.
“They are being supported by specialist search teams and the force helicopter who are searching where Alexander was last seen.
“They are also being helped by colleagues in Greater Glasgow Division who are checking around his family home on the southside of Glasgow and Shawlands where he lives.
“He is usually very active on social media but he doesn’t have his phone with him and has not been online as far as we are aware since he was last seen – which is not like him at all.
“One line of enquiry is that he may have decided to travel to London and we are making enquiries there but we cannot confirm that at this time.
“We know that he is dealing with a couple of personal issues just now but nothing that we are aware of that would suggest not being in touch with family.”
Howard and Claire Singerman, Alexander’s parents, are desperate for their son to come home or at least make contact.
They said: “Alexander is a very personable man who has a lot of friends.
“He just moved out of our home last month and moved in to a flat in Shawlands with a friend so we were in touch a lot.
“He was still coming home collecting bits and pieces in the last few weeks.
“We are all very worried and just want him to come home safe and well.
“We just want him to call us or the police to let us know he is ok.”
Anyone who knows any information or recognises Alexander, please contact the police via 101 quoting reference number 1121/10/05.
Check the Ayr Advertiser series web pages and Facebook pages for updates on the search for Alexander.