To propose a new method for estimating a step with higher accuracy.

In a navigation device 1, filtering is carried out for a detection result of an acceleration sensor 41, and walking of a user is detected by detecting a peak of acceleration in a Z-axis. The acceleration in the Z-axis filtered is used to estimate the step of the user according to a correlation model expression predetermined, corresponding to the walk speed of the user. Furthermore, the filtering is done also for a detection result of a gyro sensor 43, while integration is carried out for a filtered angular velocity around the Z-axis for estimating the walking direction of the user. The step and the walking direction estimated are used to calculate the movement path of the user.