A train slide control device and a train slide control method capable of further improving the precision of slide control are achieved. The train slide control device comprises: an electromagnetic valve unit; a relay valve that outputs a pressure of the brake cylinder; and a slide controller that includes: a velocity-difference detecting unit that detects a velocity difference of each wheel based on a velocity signal; a deceleration calculating unit that calculates a deceleration of a train based on the velocity signal; a sliding-amount determining unit that determines a sliding-amount of each wheel based on the velocity difference and deceleration; and a brake-cylinder-pressure calculating unit that calculates a pressure control signal for controlling a pressure of the brake cylinder based on:the sliding-amount; a brake command for obtaining a predetermined deceleration; and a signal that indicates the pressure of the compressed air and a pressure of the brake cylinder.