MIXING CONTAINER, MIXING CONTAINER KIT, METHOD OF USING MIXING CONTAINER OR MIXING CONTAINER KIT, AND ASSISTIVE DEVICE OF MIXING CONTAINER

A mixing container for mixing multiple materials comprises a container body in which multiple storage chambers are formed in a storage part by a partition wall that is a raised portion of a wall surface forming the storage part, and a lid member attached to the container body such that the multiple storage chambers are separately sealed; the partition wall is configured to be deformable into a concave part recessed in a movement direction of the partition wall through movement in a direction from the lid member toward the container body with a circumferential edge of the storage part sealed to the lid member; and when the partition wall is deformed into the concave part, the multiple storage chambers are deformed into one storage chamber.