To provide an attitude change controller and an attitude control method for a spacecraft capable of changing an attitude at a high speed with high accuracy.

An attitude change plan command generator 4 calculates a maximum torque value necessary for the next attitude change on the basis of an attitude change request time, a target attitude angle and an attitude rotary shaft vector transmitted as an attitude angle decision signal 18, an attitude angular velocity decision signal 19 and telemetry data 33 from a ground station 32, and outputs the calculation result as an attitude change command signal 20. An attitude change means selection device 5 compares the maximum torque value with output maximum torque values of an RW 12, an RCS 13 and a CMG 14, and selects an optimum combination of the RW 12, the RCS 13 and the CMG 14 as an attitude control actuator to be driven. The selected actuator is driven to apply torque to a spacecraft dynamics 15.