An object of the invention is to provide an electron microscope which can easily and safely prepare a gas or liquid environment in the electron microscope and can observe a specimen in the environment and a reaction of the specimen at a high resolution and to provide a specimen holder for the electron microscope. In the electron microscope including specimen holding means (6) for holding a specimen (23), the specimen (23) is placed in a capillary (17) through which electron beams are transmittable, the electron microscope includes a supply device for supplying gas or liquid into the capillary (17) and a collection device for collecting the gas or the liquid, and the electron microscope obtains a specimen image of the specimen while flowing the gas or the liquid.