LEARNING DEVICE, AND LEARNING METHOD

A learning device is configured to perform learning by gradient boosting, and includes: data memory units configured to store learning data including a type of feature amount and corresponding gradient information; gradient output units each configured to receive an input of the feature amount and the corresponding gradient information from a corresponding one of the data memory units, and output the gradient information through an output port corresponding to each value of the input feature amount; an addition unit configured to add up one or more pieces of the gradient information corresponding to the same value of the feature amount, and output an added value of the gradient information corresponding to each value of the feature amount; and a histogram memory unit configured to store a histogram obtained by integrating added values of the gradient information corresponding to each value of the feature amount as a bin.