James Bowman left the busy train station at around 3pm on Friday, March 22 and has not been seen since.
He was heading in the direction of Hope Street.
Officers are now looking for the 47-year-old and are urging anyone who recognises him to get in touch.
He is around 5ft 10ins, of slim build and was wearing a grey jacket and blue jeans.
Anyone with any information is urged to contact 101 with reference number 2421 of Friday, March 22, 2024.
