A holder support device in an electron microscope. The device has a detachable cylindrical holder extending along the X-axis. The holder support device permits the position of the inner end of the holder to be adjusted along the X-, Y-, and Z-axes and about the angular position about the X-axis. The support device has an inner cylinder rotatably held to an outer cylinder. The inner cylinder is provided with a holder through-hole and a pin guide hole. The holder is slidably held in the holder through-hole. The pin guide hole guides a pin on the holder when it is inserted into the holder through-hole. The outer cylinder is provided with a circumferential guide hole and axial guide holes.