Experiment) laser system for the Fast Ignition experiment in the laser fusion. The laser system is a CPA system, and has 4 beam lines of 40 × 40 cm size for generating the output energy of 10 kJ at the pulse duration of 10 ps with the rise-time of 1 ps. The pulse waveform was controlled with a refl ective spatial phase modulator placed at the downstream of the pulse stretcher for obtaining a fl at-top waveform at the final compressed pulse. The wavefront distortion in the main amplifier was compensated with 2 deformable mirrors for each beam-line. The pump-induced wavefront distortion was corrected with the predicted wavefront error obtained in previous shots. The wavefront error at the high power shot was improved to about 0.5 λ with this scheme.