A walking assist device (10, 10A) adapted to assist a user in performing high-quality walk in which the user swings his/her arms correctly in synchronization with a motion of the legs of the user, and that achieves a travel speed that matches the arm swing state and the walking speed which are natural for the user, said walking assist device comprising: a frame; a plurality of wheels (60FR, 60FL, 60RR, 60RL) provided at a lower end of the frame and including at least one drive wheel (60RR, 60RL); a drive unit (64R, 64L) that is configured to drive the drive wheel (60RR, 60RL) to cause the walking assist device (10, 10A) to travel forward or rearward; a battery that is configured to serve as a power source for the drive unit (64R, 64L); a drive control unit that is configured to control the drive unit (64R, 64L); a pair of right and left movable handles (20R, 20L) that are configured to be grasped by a user and that are movable back and forth with respect to the frame in accordance with arm swing performed during walk of the user; a handle guide unit (30R, 30L) provided on the frame to guide the movable handles (20R, 20L) in a movable range in accordance with the arm swing performed during the walk of the user; and a grasp portion state detection unit that is configured to detect a state of the movable handles (20R, 20L), wherein the drive control unit is configured to control a travel speed of the walking assist device (10, 10A) by controlling the drive unit (64R, 64L) on the basis of the state of the movable handles (20R, 20L) which is detected using the grasp portion state detection unit, wherein the drive control unit is configured to calculate a frame relative front-rear position (PmR, PmL), which is a position of the movable handles (20R, 20L) with respect to the frame in a frame front-rear direction which is a front-rear direction of the frame, on the basis of the state of the movable handles (20R, 20L) which is detected using the grasp portion state detection unit, and is configured to control the drive unit (64R, 64L) on the basis of the frame relative front-rear position (PmR, PmL) which matches the arm swing by the user, characterized in that the frame is comprising rails (30R, 30L), wherein the right and left movable handles (20R, 20L) are each provided on the respective rail (30R, 30L) of the frame, and the right and left movable handles (20R, 20L) are each movable in the front-rear direction along the respective rails (30R, 30L). a frame; a plurality of wheels (60FR, 60FL, 60RR, 60RL) provided at a lower end of the frame and including at least one drive wheel (60RR, 60RL); a drive unit (64R, 64L) that is configured to drive the drive wheel (60RR, 60RL) to cause the walking assist device (10, 10A) to travel forward or rearward; a battery that is configured to serve as a power source for the drive unit (64R, 64L); a drive control unit that is configured to control the drive unit (64R, 64L); a pair of right and left movable handles (20R, 20L) that are configured to be grasped by a user and that are movable back and forth with respect to the frame in accordance with arm swing performed during walk of the user; a handle guide unit (30R, 30L) provided on the frame to guide the movable handles (20R, 20L) in a movable range in accordance with the arm swing performed during the walk of the user; and a grasp portion state detection unit that is configured to detect a state of the movable handles (20R, 20L), wherein the drive control unit is configured to control a travel speed of the walking assist device (10, 10A) by controlling the drive unit (64R, 64L) on the basis of the state of the movable handles (20R, 20L) which is detected using the grasp portion state detection unit, wherein the drive control unit is configured to calculate a frame relative front-rear position (PmR, PmL), which is a position of the movable handles (20R, 20L) with respect to the frame in a frame front-rear direction which is a front-rear direction of the frame, on the basis of the state of the movable handles (20R, 20L) which is detected using the grasp portion state detection unit, and is configured to control the drive unit (64R, 64L) on the basis of the frame relative front-rear position (PmR, PmL) which matches the arm swing by the user, is configured to calculate a frame relative front-rear position (PmR, PmL), which is a position of the movable handles (20R, 20L) with respect to the frame in a frame front-rear direction which is a front-rear direction of the frame, on the basis of the state of the movable handles (20R, 20L) which is detected using the grasp portion state detection unit, and is configured to control the drive unit (64R, 64L) on the basis of the frame relative front-rear position (PmR, PmL) which matches the arm swing by the user, characterized in that the frame is comprising rails (30R, 30L), wherein the right and left movable handles (20R, 20L) are each provided on the respective rail (30R, 30L) of the frame, and the right and left movable handles (20R, 20L) are each movable in the front-rear direction along the respective rails (30R, 30L).