A 6-degree-of-freedom control apparatus for a spacecraft includes a plurality of thrusters, thruster modulator, position/velocity detector, target position/velocity generator, attitude/angular velocity detector, target attitude/angular velocity generator, and 6-degree-of-freedom controller. The thrusters control three position axes and three attitude axes of a spacecraft by jet. The thruster modulator selectively drives the thrusters on the basis of a thruster control signal. The position/velocity detector measures a position and velocity of the spacecraft. The target position/velocity generator generates target position and velocity values of the spacecraft. The attitude/angular velocity detector measures an attitude and angular velocity of the spacecraft. The target attitude/angular velocity generator generates target attitude and angular velocity values of the spacecraft. The 6-degree-of-freedom controller generates the thruster control signal on the basis of a deviation between an output from the position/velocity detector and an output from the target position/velocity generator and a deviation between an output from the attitude/angular velocity detector and an output from the target attitude/angular velocity generator and outputs the signal to the thruster modulator.