The invention relates to a superfluidhelium constant temperature bath device in the technical field of superconducting materials. The superfluidhelium constant temperature bath device comprises a flange cover, a reduced tee, a connecting piece, a vacuum sleeve, a supporting rod, a superfluidhelium cavity, a corrugated pipe and a liquid helium laminar flow limiting pipe; wherein the flange cover, the reduced tee, the connecting piece and the vacuum sleeve are connected end to end fixedly; the superfluidhelium cavity, the corrugated pipe and the liquid helium laminar flow limiting pipe are communicated end to end and fixed in the vacuum sleeve, and a sample seat to be detected is suspended and soaked in the superfluidhelium cavity through the supporting rod. The invention has small and exquisite structure, is independent and can be detached to completely separate from a liquid helium container, and does not need a liquid nitrogen container and a cold shield. A superfluidhelium generation cavity has small vacuumizing and decompressing volume, thereby greatly reducing the consumption of liquid helium; therefore, the superfluidhelium constant temperature bath device is especially suitable for long-time continuous measurement of small samples in a 1.8K-4.2K low-temperature environment.