PROBLEM TO BE SOLVED: To provide a sample preparation method and a sample preparation device for photographing an image capable of counting accurately fine particles contained in an evaluation material for evaluating mastication function.SOLUTION: A sample preparation method includes a heating step for heating a masticated evaluation material containing fine particles and sugar so as to dissolve the contained sugar, a cleaning step for cleaning the evaluation material heated in the heating step so as to remove the dissolved sugar, and a rolling step for storing the evaluation material cleaned in the cleaning step into a preparation and extending it.
