This paper describes a wearable augmented reality system with an IrDA device and a passometer. To realize augmented reality systems, the position and orientation of user's viewpoint should be obtained in real time for aligning the real and virtual coordinate systems. In the proposed system, the orientation of user's viewpoint is measured by an inertial sensor attached to the user's glasses, and the position is measured by using an IrDA device and a passometer. First, the user's position is specified exactly when the user comes into the infrared ray range of the IrDA markers which are set up to the appointed points. When the user goes out of the infrared ray range, the user's position is estimated by using a passometer. The passometer is constructed of an electronic compass and acceleration sensors. The former can detect the user's walking direction. The latter can count how many steps the user walks. These data and the user's pace make it possible to estimate the user's position in the neighborhood of the IrDA markers. We have developed a navigation system based on using the techniques above and have proven the feasibility of the system with experiments.