This paper gives an overview of recent progress of x-ray laser research in Japan Atomic Energy Research Institute (JAERI). In the development of high quality x-ray laser beam, the progress includes the improvement of output energy of fully spatial coherent x-ray laser beam at a wavelength of 13.9 nm and generation of temporally coherent x-ray laser at 26.9 nm by use of seed x-ray injection technique. Beam stability is greatly improved to be better than 0.5 mrad by introducing new designed target chamber and target alignment system. In the application of the 13.9 nm laser, an experiment by use of x-ray speckle technique reveals firstly the existence of polarization clusters in ferroelectric substance. For the purpose of further application experiments, 0.1 Hz-repetition rate x-ray laser driver is being developed, which is based on an OPCPA pre-amplifier and a Nd:glass zigzag slab amplifier with two beam lines, and each line provides 10 Joules 1 ps pulse on target.