PROBLEM TO BE SOLVED: To provide a plastic injection material that exhibits plasticity relatively in a short time and reduces variation in the strength after cured, and a method for producing the plastic injection material.SOLUTION: The plastic injection material is characterized in that a mixture comprising cement, bentonite and water is kneaded, the bentonite has a swelling power of 30 or more, a mass ratio of the water to the bentonite is 8.2 or less, and a flow value is 120 mm or less when a kneading time of the mixture is within 3 minutes.SELECTED DRAWING: None