  The energy and the width of resonance states are determined by analytic
continuation of bound-state energies as a function of the coupling constant
(potential strength). The advantage of the method is that the existing
techniques for calculation of bound states can be applied, without any
modifications, to determine the position of resonances. Various numerical
examples show the applicability of the method for three-body systems, including
the excited states of the $^6$He and $^6$Li.
