A chemicals mixing container includes: a cylinder (8) having a tubular shaped outer tube (10), and an end wall (11) which seals one end of the outer tube; an elastic partition wall (12) placed inside the outer tube to define a mixing chamber (5) within the cylinder; and an ejection auxiliary member (13) placed inside the outer tube and outside the mixing chamber, and which has an end face swollen toward the mixing chamber and moreover which is enabled to press the elastic partition wall against the end wall. The chemicals mixing container is enabled to reliably mix a liquid material and a powder material together and discharge a mixture (18) of the liquid material and the powder material without waste.