This mosque, which was used as holy shrine’s guest house during Safavid era, is visited by pilgrims. It was reconstructed during Qājār era and was known as Masjid-e Bālā Sar [the mosque at the head of the holy body of Lady Fatima Masuma (PBUH)]. It was considered the largest enclosed area of the holy shrine. In 1338 A.H, with the addition of a piece of land in the western side of the mosque the area of the mosque was increased.