A gait posture meter that evaluates a gait posture of a measurement subject includes an accelerometer affixed to a centerline of the measurement subject's waist area and a computation unit. The computation unit calculates a Z feature amount and an X feature amount indicating a degree of a difference between up-down and front-rear axis direction accelerations of the waist area in a left leg reference period and up-down and front-rear axis direction accelerations of the waist area in a right leg reference period using a timewise change waveform in three axis accelerations outputted by the accelerometer, and calculates a Y feature amount indicating a degree of a difference between a displacement of a left-right axis direction trajectory of the waist area in the left leg reference period and a displacement of the left-right axis direction trajectory of the waist area in the right leg reference period by finding a second-level integration of the left-right axis acceleration outputted by the accelerometer.