A robot and a behavior control system for the same are capable of ensuring continued stability while carrying out a specified task by a motion of a body of the robot. Time-series changing patterns of first state variables indicating a motional state of an arm are generated according to a stochastic transition model such that at least one of the first state variables follows a first specified motion trajectory for causing the robot to carry out a specified task. Similarly, time-series changing patterns of second state variables indicating a motional state of the body are generated according to the stochastic transition model such that the second state variables satisfy a continuously stable dynamic condition.