A nozzle and a combustion chamber of a small liquid fuel rocket engine used as an upper stage engine of solid propellant rocket and an apogee engine of a satellite requires to operate without cooling by cryogenic fuels. From this reason, materials that can be used at high temperature in oxidizing environment are highly required for such thrusters. To meet with this demand, trial manufacture of a thruster made of SiC fiber-reinforced SiC matrix composite are carried out in this study. A SiC/SiC composite thruster was successfully manufactured by CVI and PIP combination process. The thruster passed the proof pressurize test up to 5.0 MPa (2.5 times higher than operation pressure, 2.0 MPa). However, First trial ended in an explosion just after the ignition of the engine. By changing engine start sequence (provide fuel and oxidizer just before the ignition to avoid penetration of the liquid into the pores), 30s continuous oneration of the engine succeeded.