By using the input unit, a condition previously regarded necessary, for example, some parameter values of a plurality of frequencies are registered as a group. The registered parameter values are stored in a memory within the apparatus setting condition controlling unit. An operator selects a desired group at a diagnosis time, and selects a parameter value to be used for diagnosis, from a plurality of parameter values forming the group. The apparatus operates based on the operational condition defined by the parameter value, to make a diagnosis.