A power distribution management apparatus comprising: a history information storage unit configured to store history information including: a combination pattern of open and closed states of switches forming a path, controlled by one distribution substation, through which power is supplied between the substation and load equipment of customers and attribute information related to an environment where the power is supplied, said attribute information being associated with the combination pattern of open and closed states of switches, wherein said attribute information includes calendar information including a day of the week and a date classification indicating a workday or a holiday, and weather information including time, an amount of solar radiation and temperature; a calculation unit configured to: accept, from a client terminal, a specification of attribute information related to an environment where power is supplied; extract, from the history information storage unit, records of history information whose date classification are the same as that of the attribute information specified by the client terminal and register those records of history information in a similar pattern list; calculate, for each record of the similar pattern list, a degree of similarity between the attribute information specified by the client terminal and the attribute information included in the similar pattern list, the degree of similarity being calculated based on differences in time, amount of solar radiation and temperature between the attribute information specified by the client terminal and the attribute information included in the similar pattern list; an extraction unit configured to extract, from the similar pattern list, records of history information whose calculated degree of similarity satisfy a predetermined condition; output, to the client terminal, the combination pattern of open and closed states of switches of the extracted records of history information whose calculated degree of similarity satisfy the predetermined condition. a combination pattern of open and closed states of switches forming a path, controlled by one distribution substation, through which power is supplied between the substation and load equipment of customers and attribute information related to an environment where the power is supplied, said attribute information being associated with the combination pattern of open and closed states of switches, wherein said attribute information includes calendar information including a day of the week and a date classification indicating a workday or a holiday, and weather information including time, an amount of solar radiation and temperature; a calculation unit configured to: accept, from a client terminal, a specification of attribute information related to an environment where power is supplied; extract, from the history information storage unit, records of history information whose date classification are the same as that of the attribute information specified by the client terminal and register those records of history information in a similar pattern list; calculate, for each record of the similar pattern list, a degree of similarity between the attribute information specified by the client terminal and the attribute information included in the similar pattern list, the degree of similarity being calculated based on differences in time, amount of solar radiation and temperature between the attribute information specified by the client terminal and the attribute information included in the similar pattern list; accept, from a client terminal, a specification of attribute information related to an environment where power is supplied; extract, from the history information storage unit, records of history information whose date classification are the same as that of the attribute information specified by the client terminal and register those records of history information in a similar pattern list; calculate, for each record of the similar pattern list, a degree of similarity between the attribute information specified by the client terminal and the attribute information included in the similar pattern list, the degree of similarity being calculated based on differences in time, amount of solar radiation and temperature between the attribute information specified by the client terminal and the attribute information included in the similar pattern list; an extraction unit configured to extract, from the similar pattern list, records of history information whose calculated degree of similarity satisfy a predetermined condition; output, to the client terminal, the combination pattern of open and closed states of switches of the extracted records of history information whose calculated degree of similarity satisfy the predetermined condition.