A fan including a system for holding blades having variable pitch, in which the bases of the blades are mounted onto radial shafts of a rotor of the fan by pivots, is provided. The system includes a main body capable of being attached onto the rotor; and at least one holding arm mounted onto the main body and capable of extending inside a pivot so as to engage with the pivot in order to lock the movement of the pivot along the axis of the shaft on which the holding arm is mounted.