Abstract: A lubricating oil discharge and filling structure of an oil pan including a cylindrical lubricating oil amount adjustment wall vertically provided from a bottom surface of the oil pan, and having a lubricating oil amount adjustment passage communicating with an outside of the oil pan, formed on an inner periphery. The lubricating oil amount adjustment wall has a lubricating oil discharge hole formed in a lower part, to the lubricating oil amount adjustment passage, a cylindrical lubricating oil amount adjustment plug in which a communication hole that communicates with the lubricating oil amount adjustment passage is formed is assembled movably along the lubricating oil amount adjustment passage. The lubricating oil amount adjustment plug includes a screw portion that screws into a screw groove formed in the lubricating oil amount adjustment passage, and a sealing wall that seals discharge of the lubricating oil from the lubricating oil discharge hole.