1. A medical decision making support apparatus characterized by comprising: inference means for obtaining an inference result by performing inference processing associated with a medical diagnosis based on a plurality of pieces of input medical information; calculation means for calculating a degree of one of denial and affirmation of the inference result in association with each of a plurality of partial sets including each medical information extracted from the plurality of pieces of medical information as an element; and presentation means for presenting an inference result obtained by said inference means and negative information indicating medical information included in a partial set, of the plurality of partial sets, for which a degree of denial is calculated by said calculation means.