1. A machine learning apparatus comprising: an analytical information storage unit that stores therein two or more pieces of analytical information each associating a piece of input/output information containing information on input and information on output used for machine learning with a piece of time-point information indicating a time point of the input/output information; an analysis-object-set specifying unit that specifies an analysis object set containing a unit-period input-output set for unit periods divided in a period, the unit-period input-output set being a set of pieces of the input/output information corresponding to pieces of the time-point information indicating the time point in the unit periods and an amount of the pieces of the input/output information of the set being dependent on a period between the time point of the unit periods and a specific time point; and a machine learning unit that performs machine learning by using the pieces of the input/output information contained in the analysis object set specified by the analysis-object-set specifying unit.