Experimental techniques for sound velocity measurements and high pressure and temperature generation using Kawai-type multi-anvil apparatus have been expanded to the deeper regions of the Earth’s lower mantle. A number of new experimental results particularly relevant to the following topics have been obtained under the pressure and temperature conditions of the deep lower mantle; 1) ultrasonic sound velocity measurements on major high-pressure minerals in the mantle and subducting slabs, 2) melting temperatures, melting relations, and element partitioning among high pressure minerals of the lower mantle materials, 3) phase relations and stabilities of some major mantle minerals and hydrous minerals, leading to important implications for the chemical compositions, evolution, and dynamics of the lower mantle of the Earth.