This is the Haiden (worship hall) of Kishiki Jinja.
Kishiki Shrine, established in 1361, was originally built as a place where farmers could pray for better harvests. Now, it is most well-known for being the home of the famous Danjiri Matsuri. It is located near the remaining structures of Kishiwada-jo, and has been affiliated with the castle as the main place of worship for its daimyo. The shrine is also known as Gozutenno-sha and is a branch shrine of Yasaka Jinja in Kyoto, but the name changed to Kishiki during the Meiji era when the castle was expanded.