The invention provides a nondestructive inspection apparatus and nondestructive inspection method for inspecting the inside of a surface layer of a composite structure using cosmic-ray muons. The nondestructive inspection apparatus is to inspect the inside of the surface layer of a composite structure 11 using cosmic-ray muons 12 incoming substantially in the horizontal direction with being spin polarized by a given amount in the incoming direction, and has positron/electron amount detecting means 13 for detecting a positron/electron amount reflection-emitted having a characteristic time constant in the direction opposite to the incoming direction of the cosmic-ray muons 12 by the decay of the cosmic-ray muons 12 stopping inside the composite structure 11, and radiography data processing means 14, 15, 16 for data-processing a state of the second substance 11-2 different from the first substance 11-1 of the surface layer existing inside the surface layer of the composite structure 11 as radiography to output, from the positron/electron amount detected in the positron/electron detecting means 13.