An abnormality detection apparatus (100) includes an acquisition unit (110) that acquires input data, an abnormality degree computation unit (120) that has a discriminative model for computing an abnormality degree of input data, inputs the acquired input data to the discriminative model, and thereby computes an abnormality degree of the input data, a normality degree computation unit (130) that has a normality model for computing a normality degree of input data, inputs the input data to the normality model, and thereby computes a normality degree of the input data, a determination unit (140) that has a determination model for performing determination relating to an abnormality level of input data, inputs the abnormality degree and the normality degree to the determination model, and thereby performs determination relating to an abnormality level of the input data, and an output unit (150) that outputs output information based on a result of the determination.