To provide an evaluation device of unit consumption of fuel, in which the unit consumption of fuel can be evaluated for each cast slab.

A unit 17a for calculating the unit consumption of fuel distributes gas consumption amount in each time within a predetermined period to each slab in a weight ratio of the slab by using slab data, gas consumption amount data and weight data and calculates the unit consumption of fuel of the slab by integrating the gas consumption amount distributed to the slab for staying time in a furnace of the slab. An output device 12 outputs information on the unit consumption of fuel of the slab, calculated by the unit 17a.