A driving assistance device includes a storage medium that stores computer-readable instructions, and a processor connected to the storage medium. The processor executes the computer-readable instructions to recognize an object around a moving body, perform first control for avoiding contact between the moving body and the recognized object by steering, perform second control for avoiding contact between the moving body and the recognized object by braking, derive an estimated value of a yaw rate generated in the moving body on the basis of reference information including at least a plurality of types of information different from a measured value of a yaw rate output by a yaw rate sensor mounted on the moving body, and suppress the first control if a deviation between the measured value and the estimated value is greater than a reference.