The present invention provides an autonomous traveling work machine that can accurately receive positioning signals from navigation satellites and autonomously travel without deviating from a traveling path, even in the case of an inclined slope. The autonomous traveling work machine includes a traveling machine body, a positioning receiver that receives positioning signals from navigation satellites, an autonomous traveling control device that performs control for autonomous traveling along traveling paths based on the positioning signals, an inclination detection unit that detects the inclination of the traveling machine body and outputs inclination angle information, an inclination angle determination unit that determines an inclination angle based on the inclination angle information, and a rotation control mechanism that rotates the positioning receiver with one or more degrees of freedom. The rotation control mechanism keeps the positioning receiver horizontal based on the inclination angle.