Fr Graeme Bell, 41, and from Our Lady Star of the Sea Church in Saltcoats, Ayrshire, admitted having a gambling problem at Kilmarnock Crown Court on Tuesday.
He embezzled the money between March and May 2015.
Funds set up for pilgrimages to Lourdes and missionary work in Guyana were initially investigated but the probe was expanded to cover the whole of the parish's finances once the scale of the embezzlement became clearer.
As well as being a parish priest, Fr Bell was also an expert in church law and had dealt with disputes between bishops and priests and also marriage annulments.
The Diocese of Galloway has said it will not comment on the case until Fr Bell is sentenced next month.
It is likely Fr Bell will receive a form of counselling or therapy for his gambling addiction along with his sentence.
