Ian Stafford, 59, resigned as mayor of Preesall in Lancashire when he was arrested in connection with the missing garments.
He appeared at Preston Crown Court on Monday and pleaded guilty to three counts of burglary.
Walking with a cane, Stafford admitted breaking into the buildings in Poulton-le-Fylde and Stalmine, Lancashire, between January 1 and June 26 last year.
Female residents called in police after their underwear kept disappearing, and one victim even installed a hidden camera in her bedroom.
The case was adjourned for pre-sentencing reports until February 5 when Stafford, of Sandycroft Place, Preesall, will reappear at the court.
His barrister Richard Haworth said he had no previous convictions.
Judge Philip Sycamore gave the part-time handyman and gardener bail but told him not to "draw any conclusions" from that about his sentence.
"All sentencing options are open," he said.