The aim of the paper is to show an effective application of multiple-precision arithmetic to numerical computations of ill-posed problems. Multiple-precision arithmetic enables us to realize virtually numerical computations without rounding errors, and we apply it, without any stabilization methods, to an inverse acoustic scattering problem to obtain remarkable results. We also introduce our new multiple-precision arithmetic environment exflib, which is designed and implemented for fast computation of large scale scientific numerical simulations, and it works with the language C++ and FORTRAN90. © 2007 IOP Publishing Ltd.