This chapel is located to the south of the temple. A large bronze seated Buddha image (Phra Mongkhon Bophit) was originally enshrined outside the Grand Palace to the east. It could be dated to the 15th century. Later, King Songtham commanded it to be moved to the west, where it is currently enshrined and covered with a Mondop.The top of the Mondop was burnt down due to a thunderbolt. The King then commanded that a new building be built in the form of a big sanctuary (Maha Wihan) to cover the former one.