In this paper the sinc-Galerkin method,
as well as the sinc-collocation
method, based on the double exponential
transformation (DE transformation)
for singularly perturbed
boundary value problems of second order
ordinary differential equation is considered.
A large merit of the present method exists in that
we can apply the standard sinc method with only
a small care for perturbation parameter.
Through several numerical experiments
we confirmed higher efficiency of the present method than
that of other methods, e.g., sinc method
based on the single exponential (SE) transformation,
as the number of sampling points increases.