A damage detection apparatus and method which detect a damage occurring in a specimen include energizing an inspection area on a specimen into a predetermined energized condition, measuring a potential difference at predetermined intervals in the inspection area, and analyzing an existence or otherwise of a damage, and a shape thereof, based on a plurality of items of potential difference data. Parameters specifying a hypothetical damage are hypothesized in advance and, based on the potential difference data, calculation is executed using a maximum likelihood estimation method on a double body in which hypothetical specimens are doubled by bringing together their front surfaces, and furthermore on a quadruple body quadrupled by bringing rear surfaces of hypothetical specimens together, a maximum likelihood estimation value of the parameters is calculated.