A turbomachine module with a longitudinal axis, the module comprising: a rotary casing rotatable around the longitudinal axis and arranged to carry a propeller provided with a plurality of blades; a system for changing the pitch of the blades of the propeller comprising: a control, and a mechanism for varying the pitch of the blades of the propeller connecting these blades to the control, wherein the control comprises a rotary actuator comprising a control body and a reference body which is integral with the rotary casing, and wherein the mechanism for varying the pitch comprises a synchronization ring which is driven in rotation around the longitudinal axis by the control body and which is guided in rotation on the rotary casing, the synchronization ring being connected to the blades.