The present invention provides a hydraulic circuit for a crane wherein a switching valve is provided between a plurality of motor circuits connected in series within the same actuator group, and at the time of simultaneous operation of the motor circuits, the switching valve is switched from a first position to a second position whereby the series connection between the motor circuits is cut off, and they are driven by each of separate hydraulic sources, thereby enabling prevention of pressure interference at the time of simultaneous operation of the motor circuits within the same actuator group without increasing hydraulic sources.