A sample introduction device for introducing a sample into a sample chamber of a charged particle beam instrument, said sample introduction device comprising: a sample holder; an insertion tube extending toward the sample chamber and rotatable about the axis of the tube; a pre-evacuation chamber inside the insertion tube for performing a pre-evacuation; a partition valve for isolating said pre-evacuation chamber and said sample chamber from each other, said partition valve opened and closed by rotation of the insertion tube; a goniometer for rotating said insertion tube and sample holder; said sample holder linearly movable within the insertion tube having a sample holding portion capable of holding the sample; and a linearly movable support portion for supporting the sample holder; mechanical drives for moving the support portion such that the sample holding portion moves from inside the pre-evacuation chamber into the sample chamber, characterised in that the sample introduction device further comprises a controller for controlling said mechanical drives and the goniometer; wherein the controller is configured to perform an operation for controllably rotating the goniometer to open or close the partition valve, an operation for causing the mechanical drives to move said support portion such that the sample holding portion moves from inside the pre-evacuation chamber into the sample chamber, and an operation for causing the mechanical drives to move the support portion away from the sample holder, and wherein said mechanical drives and said controller are configured, when a first force is applied to said sample holder by a pressure difference between the interior of said sample chamber and the outside, to apply a second force to the sample holder, which second force is opposite in sense to and smaller than the first force. a sample holder; an insertion tube extending toward the sample chamber and rotatable about the axis of the tube; a pre-evacuation chamber inside the insertion tube for performing a pre-evacuation; a partition valve for isolating said pre-evacuation chamber and said sample chamber from each other, said partition valve opened and closed by rotation of the insertion tube; a goniometer for rotating said insertion tube and sample holder; said sample holder linearly movable within the insertion tube having a sample holding portion capable of holding the sample; and a linearly movable support portion for supporting the sample holder; mechanical drives for moving the support portion such that the sample holding portion moves from inside the pre-evacuation chamber into the sample chamber, characterised in that the sample introduction device further comprises a controller for controlling said mechanical drives and the goniometer; wherein the controller is configured to perform an operation for controllably rotating the goniometer to open or close the partition valve, an operation for causing the mechanical drives to move said support portion such that the sample holding portion moves from inside the pre-evacuation chamber into the sample chamber, and an operation for causing the mechanical drives to move the support portion away from the sample holder, and wherein said mechanical drives and said controller are configured, when a first force is applied to said sample holder by a pressure difference between the interior of said sample chamber and the outside, to apply a second force to the sample holder, which second force is opposite in sense to and smaller than the first force.