1. A pattern classifier device for determining whether an input pattern belongs to a class that is divided into a plurality of subclasses, the device comprising a processor that operates as: a reception unit that receives the input pattern and attribute information of the input pattern; a decision unit that decides the subclass to which the input pattern is to belong, based on at least the attribute information; an execution unit that determines whether the input pattern belongs to the class, using a weak classifier allocated to the decided subclass, and outputs a result of the determination and a reliability of the weak classifier; a calculator that calculates an integrated value obtained by integrating an evaluation value based on the result of the determination and the reliability; and a determination unit that determines whether a termination condition of determination processing performed by the decision unit, the execution unit, and the calculator, has been satisfied, repeats the determination processing when the termination condition has not been satisfied, and terminates the determination processing and output the integrated value at the time of the termination when the termination condition has been satisfied.