A chassis device is provided and includes a case and an operating assembly. The case is for installing a detachable module and includes a first pivoting component pivotally connected to the detachable module, a second pivoting component pivotally connected to the first pivoting component, and a first engaging component movably disposed on the first pivoting component and for removably engaging with a second engaging component of the detachable module. The first pivoting component is restrained from pivoting when the first engaging component engages with the second engaging component of the detachable module, and when the second pivoting component pivots, the second pivoting component pushes the first engaging component, so that the first engaging component disengages from the second engaging component of the detachable module for allowing the first pivoting component to pivot. Furthermore, a related electronic apparatus and a related operating assembly are also provided.