  The overlap (inner product) between the ground-state eigenvectors with
proximate interaction parameters, the so-called fidelity, plays a significant
role in the quantum-information theory. In this paper, the critical behavior of
the fidelity susceptibility is investigated for the two-dimensional
tranverse-field (quantum) Ising model by means of the numerical diagonalization
method. In order to treat a variety of system sizes N=12,14,...,32, we adopt
the screw-boundary condition. Finite-size artifacts (scaling corrections) of
the fidelity susceptibility appear to be suppressed, as compared to those of
the Binder parameter. As a result, we estimate the fidelity-susceptibility
critical exponent as \alpha_F =0.715(20).
