A presentation device is configured to present a plurality of recognition objects to a test subject. An input device is configured to allow the test subject input an answer of a work problem as a mental work to each recognition object. The work problem includes: a work of extracting two or more kinds of prescribed cognitive elements included in each recognition object； and a work of choosing, from a plurality of options, an option suiting to the two or more prescribed cognitive elements extracted from the recognition object. The number of the plurality of options is the number of combinations of selections set to each of the two or more kinds of prescribed cognitive elements. The evaluation device includes a work memory part configured to store, as work information, an answering time from a time when the recognition object is presented on the presentation device to a time when the answer is inputted into the input device. Also, the evaluation device includes an evaluating arithmetic part configured to calculate an evaluation value of a concentration ratio of the test subject using a statistics value of the work information stored in the work memory part while the plurality of recognition objects are presented on the presentation device.
