In the present study, the influence of the slurry temperature and the gate velocity on the apparent density of molded products was investigated using a thixomolding machine and a die having a rectangular parallelepiped cavity. Magnesium alloy of AZ91D was injected into the cavity through a rectangular gate. The gate velocity was varied from 0.4 m/s to 6.0 m/s and the slurry temperature was changed between 853K and 903K, respectively. The die temperature was fixed at about 513K. The results were as follows. The apparent density of the molded products at a constant gate velocity was decreased gradually with an increase in the slurry temperature in cases the slurry temperature was lower than 863K, however, it decreased suddenly at around the slurry temperature of 873K, and then it took an almost constant value when the slurry temperature was over 873K. The apparent density of the molded products at a constant slurry temperature was decreased greatly with an increase in the gate velocity in the case the slurry temperature was over 873K, however, it decreases slowly as the gate velocity increased for cases the slurry temperature was under 863K.