Service robots as a new technology, while very useful in some respects, are by nature dangerous in others because of intimate contact with human being. Once a fatal accident occurs, service robots may be branded as unreasonably dangerous products having generic risks. Thus, the criterion of their safety validity and the treatment of the associated residual risk should be critically appreciated. This paper examines both the safety test procedures taken in the ISO/IEC safety standards as an ex ante measure and the tort litigation including products liability in USA as an ex post measure. Taking into account the characteristics of both the measures, we propose a judgment test procedure for certifying the safety of service robots as follows: 1. Risk reduction by safety design according to a priori safety principles (ISO/IEC standards for safety of machinery), 2. Risk judgment test according to the ALARP (As Low As Reasonable Practicable) principle or risk-utility test, 3. Specification of hazards causing the residual risks in the ALARP region an Critical Hazards (CHs) when they are so significant as to cause a fatal accident, 4. Test of validity of the risk reduction measures for CHs according to the Reasonably Alternative Design (RAD) standard in the tort litigation.