Disclosed is an observation apparatus and method using an electron beam, capable of measuring stress and strain information on a crystal structure in a specimen using electron beam diffraction images. A method according to the invention includes mounting a specimen on a specimen stage; irradiating a predetermined area in the specimen with an electron beam while scanning the electron beam, and acquiring an enlarged image of a specimen internal structure in the predetermined area; irradiating a specific portion included in the predetermined area and acquiring a diffraction image showing the crystal structure in the specimen; extracting information on the crystal structure in the specimen; displaying the information of the crystal structure in the specimen so as to be superimposed on the acquired enlarged image. The observation method according to the invention can obtain information on the crystal structure in a specimen with a high degree of sensitivity and with a high level of resolution.