Jeffrey Carney, 76, a former head of St Sebastian’s Primary in Nine Mile Ride, Wokingham, appeared at Reading Crown Court on Monday.
He had admitted seven charges at Reading Magistrates’ Court last month which relate to the touching of boys up to the age of 11 between 1976 and 1997.
Carney denied six counts of gross indecency, which the prosecution said it would not contest.
Judge Peter Ross said Carney should expect a custodial sentence when he appears in court for sentencing on January 27.
Carney, from Burney Bit, Tadley, was jailed for 15 months in 2003 after pleading guilty to three counts of indecent assault, relating to incidents in 1976, 1980 and 1997.