Dean Holderness's van was involved in a collision with cyclist Stuart Lees, 50, on the A1104 at Snape Hill, Saleby, near Alford in March 2020.
Mr Lees was airlifted to hospital with serious injuries but Lincolnshire Police confirmed on April 1, 2020, that he had died.
Holderness, 36, of Marston Crescent, New Lodge, Barnsley, was initially charged with the more serious offence of causing Mr Lees' death by dangerous driving, which he denied.
But on the second day of his trial at Lincoln Crown Court, Holderness pleaded guilty to a count of causing death by careless driving on the A1104 on March 23, 2020.
Crown Prosecution Service offered no evidence on the original charge and the jury were discharged from reaching a verdict.
Judge James House KC adjourned sentence for the preparation of probation and psychological reports.
Holderness was bailed to be sentenced on March 6