To easily identify the authenticity and denomination of bills of many denominations.

A bill identification device 1 comprises a conveying part 2 for conveying a bill M inserted from a slot E, a transmitted light quantity sensor 5 for radiating light to the bill M in the conveying direction of the bill M and detecting a transmitted light quantity transmitted through the bill M, and a control part 11 having a light quantity computation part 11a and a bill identification part 11b. The light quantity computation part 11a calculates a difference (transmitted light quantity difference) between a reference transmitted light quantity set for respective combinations of denominations and insertion directions and the transmitted light quantity through the bill M in every divided area of the bill M divided in the conveying direction of the bill M, and integrates the transmitted light quantity difference in all the divided areas of the bill M to compute a total transmitted light quantity difference X. The bill identification part 11b identifies the denomination and authenticity of the bill M according to the total transmitted light quantity difference X calculated by the light quantity computation part 11b.