Enhancement of chirality near plasmonic objects has been investigated in terms of circular dichroism and optical activity. Here, we examine plasmonic effects on chirality, which is the most fundamental quantity in describing chiral medium, using generalized wavenumber eigenvalue simulation. Generalization of wavenumber eigenvalue simulation from isotropic medium to bi-isotropic medium is presented. Enhanced chirality of the composite material of chiral medium and plasmonic sphere is calculated for a variety of geometrical and optical properties of the sphere. This method enables eigenvalue simulation of more general bi-isotropic medium including natural chiral materials.