An advancing direction measurement device capable of being used as a navigation device for a walker, the device being used indoors where a GPS cannot be used and at a place in the vicinity of a high-rise building where sufficient positioning accuracy is not achievable. An acceleration detection section (1) detects three-axis acceleration, varying as the walker walks, of the advancing direction measurement device, and an acceleration output data acquisition section (2) repeatedly obtains, by the number of times equal to or greater than a predetermined level, the three-axis acceleration output data varying as the walker walks and detected by the acceleration detection section (1). When the walker walks while holding the advancing direction measurement device in a substantially fixed attitude, a first gravitational acceleration calculation section (3) calculates gravitational acceleration by averaging acceleration data groups being within a time period corresponding to several walking steps and obtained by an acceleration output data acquisition section (2). Then, a first movement direction estimation section (4) estimates the direction of movement of the walker based on a frequency component corresponding to a time period of one step of acceleration data projected on a plane that is orthogonal to the gravitational acceleration calculated by the first gravitational acceleration calculation section (3).