NOVELTY - The size of metal nano particles is changed into movable state of nanometer level by placing the raw material metal (23) in a crucible (22) and evaporating the metal in a decompressed atmosphere or vacuum. A surfactant (26) present in the chamber is made into flowing state by controlling the temperature of surfactant, in order to dissolve the surfactant in solvent at pressure-reduced atmosphere or vacuum. The surfactant is formed into film-shape mobile component by rotating along rotating inner wall (21a) of a vacuum chamber (21) to obtain metal nanoparticles colloid (27).    USE - Multi-metal nanoparticles colloid. Uses include but are not limited to automobile, battery, wiring and electrode formation, electromagnetic shielding, electronics such as semiconductor, biosensor, biotechnology, bio-marker, printing, fuel cell, etc.    ADVANTAGE - The multi-metal nanoparticles colloid is economically manufactured, with high purity.    DETAILED DESCRIPTION - Multi-metal nanoparticles colloid is produced through heat-processing without depending on chemical reduction action. The size of metal nano particles is changed into movable state of nanometer level by placing the raw material metal in a crucible and evaporating the metal in a decompressed atmosphere or vacuum. A surfactant present in the chamber is made into flowing state by controlling the temperature of surfactant at the temperature more than the melting point of surfactant, in order to dissolve the surfactant in solvent at pressure-reduced atmosphere or vacuum. The surfactant is formed into film-shape mobile component by rotating along rotating inner wall of a vacuum chamber to obtain metal nanoparticles colloid, and the process is repeated to increase the concentration of metal nanoparticles in the colloid. The metal nanoparticles colloid consists of solvent-free surfactant of film-shape surfactant. The surfactant does not contain solvent and/or dispersant of metal nanoparticles. The multi-metal nanoparticles colloid comprises metal nanoparticles with 2 or more different nanometer levels.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the manufacturing apparatus of multi-metal nanoparticles colloid.    Vacuum chamber (21)    Inner wall of vacuum chamber (21a)    Crucible (22)    Raw material metal (23)    Surfactant (26)    Metal nanoparticles colloid (27)