The plant of the church - excluding the altar -  is a square and reminds of a Greek cross. The central room has a circular, nearly flat roof.

The main altar is made of polychrome marble and hosts a huge mixtilinear painting by Pietro Ligari, which portrays Mary wih the Child between Saint Augustine, a soldier, a cherub and Saint Thomas (1742).

Above the painting, a polychrome Venetian window portrays the Cross in the middle and, on the sides, Saint Augustine and Saint Thomas. On the sides of the main altar there are two other paintings by Pietro Ligari: one portraying the Annunciation of Saint Anne's pregnancy and the other the birth of Mary.