Abstract: In this grease composition, a grease produced by mixing at least one base oil selected from a mineral oil-type lubricant base oil, a synthetic lubricant base oil, and a biodegradable lubricant base oil with a thickener is compounded with a wax and water, and an additive such as a surfactant and a defoamer is optionally compounded therewith. A soap containing a calcium sulfonate complex is used as the thickener. A carnauba wax is preferably used as the wax. Since this grease composition is mainly composed of a grease and a wax, the grease composition extremely facilities its removal operation after application, is environmentally friendly, and has extremely excellent anti-corrosion performance. When the grease composition is used by being applied to a base material of an object to be welded, an effect of preventing the adhesion of welding spatters can be obtained.