This two-storey building, situated to the east of Waikun Thepayasathan Hall, was constructed later than the other buildings, presumably on the site of an old storehouse. Compared with the others, it is much simpler and the roof is less steep. The walls and ceilings do not have frescos as do those of the other buildings. The walls, however, are decorated with white glazed tiled. The emphasis is on the front entrance and the main staircase with art-nouveau wrought iron railing. The building also features a spiral staircase, which was made entirely of wrought iron, an indication that great progress had been made regarding construction materials. This type of staircase was popular in the reign of King Rama V but it was generally made of wood. There are two identical sets of rooms on the upper floor, one on each side of the main staircase. The first floor was a large hall. The building was originally a separate unit, not connected with the first three buildings. Later it was necessary to turn the building into residences for Phra Nang Chao Suvadhana and Phra Sutcharit Suda, A long span bridge of reinforced concrete was then built to join the second floor of this building to that of Waikun Thepayasathan Hall, another indication of advances in structure.