An original estimation apparatus of professional competence in the specialists training system is offered. This apparatus includes the calculation algorithm of the professional competence factor, which allows to diagnose the quality of the professional training and is an efficient instrument (the method), used for estimation of specialist's readiness degree for productive decision of the professional tasks. Use of the algorithm in practice of the high school management activity promotes revealing of the development prospects of the trained specialists and allows solving problem of effectiveness increasing of the graduates use.