1. A pattern recognition apparatus that combines and constructs multiple systems to improve recognition performance, comprising: a first system having a first model and a first decoder, which outputs a recognition result of the first system, the recognition result of the first system having a first output tendency; a second system having a second model, a second decoder, and a feature transformer, the feature transformer being configured to transform a received feature vector, which is input externally, based on the second model, which has been trained in advance based on the recognition result of the first system, and the feature transformer transforms the feature vector to produce a transformed feature vector that is decoded by the second decoder to output a recognition result of the second system, the recognition result of the second system having a second output tendency; a discriminative training unit that constructs model parameters of the second model in the second system based on the first output tendency of the recognition result of the first system so the second output tendency of the recognition result of the second system is different from the first output tendency of the recognition result of the first system; and a recognizing unit that recognizes a speech pattern or a character pattern in the received feature vector based on the recognition result of the first system and the recognition result of the second system.