Provided are a mobile robot device and a control method thereof. The mobile robot device comprises: a driving unit; an image sensor; a plurality of geomagnetic sensors; a memory for storing at least one instruction; and a processor for executing at least one instruction, wherein the processor may obtain, while the mobile robot device moves by means of the driving unit, a plurality of image data through the image sensor and obtain sensing data through the plurality of geomagnetic sensors, extract a feature point from the plurality of image data and obtain key nodes on the basis of the feature point, obtain a node sequence on the basis of the sensing data, generate a graph structure that estimates a position of the mobile robot device on the basis of the key nodes and the node sequence, and correct the graph structure based on the mobile failing in position recognition.