The importance of the inspection of concrete structures has recently increased because of the ageing of the structures and for the prevention of accidents. The commonly used methods for inspection include visual confirmation and hammering inspection. An inspector marks and sketches the types, scale, and positions of defects on the structures through drawing, and assesses the status of concrete structures based on the number, types, and scale of defects. However, while performing this task, several problems exist in terms of workload, inspection accuracy, and management. To solve these problems, the mixed reality (MR) technology is used. The functions of sketching on the MR device to reduce the burden of inspectors and overlapping an internal structure to a real structure are developed. MR is being widely applied and is attracting considerable attention because it improves work efficiency. However, MR has not been widely used for structural inspection. Therefore, the purpose of this study is to consider the novel application of MR in structural inspection and investigate its effectiveness. We use Microsoft HoloLens and consider the method of utilization of MR for visual confirmation, hammering inspection, and state assessment of structures. In particular, we consider the visualization of hitting point on hammering inspection, the function of sketching on the MR device, and the method of showing the obtained inspection information to the inspectors on the MR device. Thus, although MR has the potential to significantly reduce workload and improve inspection accuracy, its practical application necessitates the development of advanced technology.