An impression material automatic kneading apparatus where packages can be replaced easily is provided. An impression material automatic kneading apparatus (1) that kneads and discharges at least two kinds of pasty materials which form a dental impression material, the apparatus includes a holder (10) that holds a package (20) which is a container like a bag, the package containing the pasty materials and a main body (2) that is connected to an opening part (21) of the package, sucks the pasty materials from the package, and kneads said at least two kinds of pasty materials. The holder includes: a holding member (11) that holds the opening part of the package a moving member (15) that holds an end part that is in a side opposite to the opening part of the package, the moving member movably arranged along the holding member and an elastic member (19) one end of which is attached to the holding member and another end of which is attached to the moving member. The holder can be attached to and detached from the main body in a state where the package is energized by the elastic member.
