This study is aimed at developing a simple and clinical tool using a mini gyro sensor. A mini gyro sensor is a cube of 3.5 cm size which can measure the angle of motion in 3 dimensions (roll, pitch, yaw). We use 3 sensors and put them on the top of the head, spur of Th 1 spine and spur of S 1 spine. Each sensor measured the motion of head, trunk at the height of shoulder, and pelvis. We evaluated the motion in walking of a stroke patient and normal subjects. The stroke patient had larger movements than normal subjects. We also examined one cerebral palsy patient who was diplegic and walked by swinging the trunk without cane and brace. The angles of motion were large. When the patient used a bilateral crutch and wore bilateral AFO, the angles were decreased. These data suggests the possibility to analyze the characteristics of walking and the effect of treatment.