The auditorium of the castle theatre covers roughly a half of the theatre hall (c. 10x10 m). It has shape of slightly elongated horseshoe, which is approached by balcony supported by four pillars with the volutes capitals and painted fluting. In the front part of the ground floor there is space for orchestra, which is divided from the rest of the auditorium by a low wooden parapet. Similar parapet divided even back part of auditorium until the reparation in 1973. The auditorium is painted by neoclassicism decorative painting (the author is Dominik Dvorák) with soft body-color; pink, gray and chartreuse.

In the back part of the auditorium there are two staircases leading to the upper level - to the corridor with boxes. Entrance to the boxes is from the auditorium as well as separate entrances from the castle gallery courtyard. The main entrance leads from the courtyard to the back part of the auditorium; there is the entrance to the front part of the auditorium from the corridor adjacent to the theatre.

The center part of the gallery is occupied by the count box with door leaf, which is decorated by oil paintings of dancers in neoclassicist robes on the walls. There are two continuous one-piece spaces along the count box. Two separate boxes are situated in the parts, which is the closets to the stage. From these boxes there is the entrance right to the backstage.

The auditorium on the ground floor is equipped by wooden benches without backboards. There are two quarter circular lounges in the count box and several benches with backboards in the side boxes. The benches were originally spread with red leather, which is nowadays replaced by imitation leather. The neoclassicism decorative painting on the parapets of the boxes is replenish with red papery curtains with golden borders. The stage portal is decorated by golden sawn Wallenstein-Warttemberk's coat-of-arm, over the count box we can find alliances coat-of-arm of Hohenfeld's and Wallenstein-Warttemberk's families. The lyre is situated into the laurel with sparkle of golden beams in the middle part of the ceiling. The orchestra pit used be equipped by music stands for the orchestra.