An aqueous
cutting liquid comprises a cationic water-soluble resin having an amine value of 20 to 200 mgKOH / g, and at least one
rheology control agent selected from the group consisting of an inorganic
bentonite, an organic
bentonite and an aqueous silica
sol, wherein the content of a nonvolatile matter of the
rheology control agent is 0.1 to 30 percent by weight of the amount of the nonvolatile matter of the cationic water-soluble resin. An aqueous
cutting agent comprises the aqueous
cutting liquid, and an
abrasive grain, wherein the content of the
abrasive grain is 100 to 1000 percent by weight of the amount of the nonvolatile matter of the aqueous cutting liquid. A hard and brittle material is
cut by a cutting device using the aqueous
cutting agent. The present invention provides an aqueous
cutting agent which is excellent in
dispersion stability of the
abrasive grain and
viscosity stability during cutting /
slicing operations, aqueous cutting liquid
usable for the aqueous
cutting agent, and a cutting /
slicing method excellent in cutting performance,
cleanability and the like of the work material on cutting /
slicing hard and brittle material by using the cutting agent.