To prevent a furnace core pipe from being clouded owing to vapor from a sample to prevent observability from being lowered.

An inner cylindrical pipe 12 including a sample holder 13 provided on an inner bottom is concentrically disposed inside a furnace core pipe 4 of an electromagnetic floating furnace. An upper inner cylindrical pipe 14 is inserted into the inner cylindrical pipe 12 from an upper portion such that a lower end thereof reaches a slightly upper position of a sample floating position 6 located therein, and a protrusion 15 of an upper end of the inner cylindrical pipe is mounted on an upper furnace core pipe support member 5a. An inner peripheral surface of the inner cylindrical pipe 12 is subjected to slide on an outer peripheral surface of the upper inner cylindrical pipe 14 for vertical relative displacement therebetween. An upper end of an elevation rod 17 of an inner cylindrical pipe movement mechanism 16 is coupled with the lower end of the inner cylindrical pipe 12. Even when heated and melted sample 7 in floating at a sample floating position 6 under fine gravity environment is vaporized, the inner surface of the furnace core pipe 4 is prevented from being contaminated owing to the inner cylindrical pipe 12. Further, a clear portion of the furnace core pipe protected by the upper inner cylindrical pipe 14 is exposed by descending the inner cylindrical pipe 12 to prevent observability of the furnace core pipe from the side surface of the same from being obstructed.