The 17 year old, who cannot be named for legal reasons, appeared at Winchester Crown Court on Monday 14th, and has been on youth remand at a unit in Nottingham since his arrest.
The first charge relates to an incident on June 16, when the teenager set fire to a bible belonging to All Saints Church, and the second to the blaze that saw the 153-year-old building gutted on June 22. He pleaded guilty to both.
All Saints Church, in Church Road, was gutted by fire, which started at around 5.30pm and flames tore through the roof.
Fire crews battled to control the blaze and brought the fire under control by around 9.30pm.
A children's ballet class was evacuated from the adjacent church hall at around 5.40pm, after the fire broke out.
There will be a public meeting on September 19 at 10am in the parish community centre next to the church, followed by two more on September 24 at 7.30pm and October 10 at 10am.
Defending, Katherine Kelleher said that solicitors ordered for a psychiatric report to be completed before the hearing, however it was not, and she requested that sentencing should be adjourned.
The boy will be sentenced at Winchester Crown Court on October 26.