An assessment device (1) according to the present disclosure includes a determination unit (10) that determines a first period corresponding to a shortest period until deterioration of a concrete structure due to an aging-induced deterioration cause appears and a second period shorter than the first period and corresponding to a longest period until deterioration of the concrete structure due to a material-induced deterioration cause appears and an assessment unit (20) that assesses that a deterioration causing material is used in a concrete structure having, in a checking result indicating a period elapsed from construction of the concrete structure and the presence or absence of deterioration in the concrete structure, the deterioration and the period elapsed from the construction which is not shorter than the second period and is shorter than the first period.