In the northwestern compartment of the building there is a cruciform in plan – a mosque. It is covered by a double dome. For the formation of the square base of the dome, here for the first time in the architecture of Central Asia, designs with intersecting arches were used. Through the openings of sixteen windows arranged in a completely stalactite-covered dome, light falls on the stucco decorations of niches and sails. The main entrance to the mosque in the corridor of the Dzhulbars Khan is distinguished by an arched niche decorated in the upper part with ganch stalactites.