A hearing assistance suitability determining device (120) according to the present invention is a hearing assistance suitability determining device (120) which determines a suitability (153) of a subject for dichotic hearing assistance, and includes: a hearing ability information obtaining unit (130) which obtains left-ear hearing ability information (150) and right-ear hearing ability information (151) each of which indicates a hearing ability for frequencies a hearing ability type determining unit (131) which determines, among hearing ability types each of which is defined by a tendency in a change of the hearing ability with respect to the frequencies, a hearing ability type (152) of the hearing ability indicated by the left-ear hearing ability information (150) and the right-ear hearing ability information (151) and a suitability deciding unit (132) which determines, with reference to a suitability database (144), the suitability (153) of the subject for the dichotic hearing assistance based on a suitability corresponding, in the suitability database (144), to the hearing ability type (152) determined by the hearing ability type determining unit (131), the suitability database (144) showing a correspondence relationship between each of the hearing ability types and one of suitabilities of the subject for dichotic hearing assistance.