Abstract: Herein disclosed are a vacuum-degreasing cleaning method for degreasing a work by cleaning it with a solvent vapor under reduced pressure, and a vacuum-cleaning machine for practicing the method. This method comprises the vapor-cleaning step of cleaning the work under reduced pressure with a vapor of a petroleum solvent, and the drying step of drying the surface of the work under reduced pressure. This cleaning method can clean the work while preventing the deterioration of the working atmosphere and the air pollution and can reduce the initial cost and the running cost for the work cleaning operation. Moreover, the cleaning efficiency can be safely enhanced with neither any thermal influence upon nor any rust upon the work.