A tilt structure allows the tilt of a console to be changed through simple motion and has a simple configuration. The tilt structure includes: a second frame attached to an upper portion of a first frame and is swingable upward and downward; and a control member attached to the second frame and is tiltable backward and forward through a tilting shaft. The control member includes a guide part with a groove housing a first frame pin. A locked and unlocked state switch to each other by causing the control member to tilt. The locked state includes a pin engaged with any of the engagement parts. The unlocked state includes the pin disengaged. The tilt of the second frame relative to the first frame is changed by engaging the pin with an arbitrary engagement part of any of the engagement parts and changing a distance between the tilting shaft and pin.