To provide a hydraulic circuit which can switch a speed for rotating a rotational mechanism in multiple stages, and achieves the switching at a low cost.

The hydraulic circuit is provided with hydraulic motors operable by pressure oil supplied from hydraulic sources 5, and drives the single rotational mechanism 4 by operations of the hydraulic motors. The hydraulic circuit is formed of: the multiple (three or more) hydraulic motors 1a, 1b and 1c each having an output shaft 2 connected to the rotational mechanism 4; and direction switching valves 10, 11 which switch the circuit so as to serially supply the pressure oil from the hydraulic sources 5 to the multiple hydraulic motors 1a, 1b and 1c, or to supply the pressure oil to selected two or more of the hydraulic motors in parallel.