Abstract: In an electron beam apparatus such as a transmission electron microscope, a specimen holder device which comprises a specimen holder member and a holding rod connected thereto is withdrawably inserted in a pole-gap defined between upper and lower poles of an objective lens of the electron beam apparatus. An opening having a greater diameter than that of the pole end face is formed in the specimen holding member at a center portion for receiving therein a specimen mesh of a reduced thickness. A recess is formed in the specimen holding member at that portion which is caused to pass between the upper and lower magnetic poles upon insertion and withdrawal of the specimen to and from the interpole gap so that a region resulting from the formation of the recess has a reduced thickness as compared with the remaining region of the specimen holder member. Inter-pole gap of the objective lens is thus reduced to increase resolving power thereof.