Former Premier League referee David Coote, 43, pleaded guilty on Tuesday to making an indecent image of a child.
Appearing at Nottingham Crown Court, Coote entered the plea concerning an allegation relating to a Category A video, the most serious kind, recovered by Nottinghamshire Police in February.
Coote had initially pleaded not guilty to the charge in September.
He was granted conditional bail and is scheduled to return to court for sentencing on December 11.
Judge Nirmal Shant KC has ordered a pre-sentence report.
Coote was sacked from his previous position last year following controversial comments about former Liverpool manager Jurgen Klopp.
