Alastair Carmichael, 49, was last seen at his home by his family in Dumbarton on Friday evening. But police were alerted after he failed to turn up for work yesterday.
His relatives are growing increasingly concerned for him as he does not have any money or his mobile phone.
Officers are sifting through CCTV images in Dunbartonshire for clues to his whereabouts.
Inspector Claire Miller of Police Scotland said: "Alastair has recently being going through some personal issues and has never been missing before. He did not turn up for his work this morning which is completely out of character. He does not have his mobile phone or any money with him and his family and police are becoming increasingly concerned for his safety."
Mr Carmichael, who wears glasses, is described as white, 5ft 8ins tall, of stocky build with grey receding hair. He was last seen wearing blue jeans, a light blue polo top, black lightweight jacket and Voi trainers.