James Garner 33, was last seen on Bar Lane, Wakefield, at 11.20am on Monday May 10.
West Yorkshire Police said there have been no confirmed sightings of him since then as they launch an appeal for information.
James is described as a white man, 5ft 5ins tall, with balding brown hair.
He was wearing a black jumper, blue jeans and yellow Timberland boots when he was last seen.
Inspector Gary Hobson, of Wakefield District, said: "The police and Mr Garner's family are concerned for his welfare.
"We would ask anyone who has seen him or with information about his movements or current whereabouts to please contact the police.
"Similarly, we would ask Mr Garner himself to make contact with us so that we can confirm he is safe and well."
Anyone with information is asked to contact police either by calling 101 or by using the 101 Live Chat facility on the West Yorkshire Police website, quoting log number 654 of 10/05.