Abstract: A mobile crane is disclosed, particularly adapted for a towing truck, as including a boom which may be extended or retracted in length and angularly related for lifting and towing purposes by a pair of hydraulic rams, which are specifically oriented for their full extent of movement at an acute angle relative to the plane of the bed of the truck upon which the hydraulic rams are pivotally secured. Extension and retraction of the boom is provided by a hydraulic ram mounted within the boom and arranged when activated to extend the boom outwardly during the pick up of a load and the retraction prior to towing of the load. The boom is pivotally mounted on a mast structure which is braced against a pivot structure secured to the bed of the truck and to which the hydraulic rams are pivotally mounted.