To provide a dental impression material kneading device for discharging each paste of a dental impression material comprising two kinds of pastes having different fluidities at the time of feed start with a mixing ratio selected and set among two or more gradual mixing ratios, and mixing and kneading each paste in a mixer body, the device comprises a prescribed rate feed pump 4 for feeding one paste at a fixed flow rate, a set rate feed pump 5 for feeding another paste at a flow rate more than that of the prescribed rate feed pump 4, and a control means 8 for rotatively driving a rotational axis for engaging a stirring rod 2a when receiving a signal from a starting switch 8a, collating starting times of both pumps 4 and 5 corresponding to mixing ratio selected and set by a mixing ratio selection switch 6 corresponding to two or more gradual mixing ratios memorized in the starting time memory means 7, starting the both pump 4 and 5, and feeding the paste at the flow rate corresponding to the selected and set mixing ratio by the set rate feed pump 5.