PROBLEM TO BE SOLVED: To solve the problems that there are: a tokamak system for shutting in plasma by magnetic force; and an inertia (implosion) system for irradiating a fuel pellet with a laser, etc. in a conventional nuclear fusion reactor, however, the systems are still at a stage of an experimental reactor, and it is far from a practical use level, a frontal collision type nuclear fusion reactor of an ion beam using a linear accelerator is suggested before, however, an examinations on pulse operation, Coulomb repulsion are insufficient.SOLUTION: A system for making pulse electric field type accelerators face each other on one center line to cause frontal collision of neutral particle group beams is used. The beams are made to intersect at a center point of a spherical pressure container for the required number, several thousands of accelerators. Nuclear fusion reaction (artificial sun of 1 cm) is generated by the frontal collision of the pulse-driven and synchronized neutral particle groups.