A motorized valve is made up of a closable pipe, of a valve shutter, of a rotary electromagnetic actuator and of an overmoulding plastic material, the actuator being formed of a stator assembly, of a rotor secured to a spindle, the valve shutter being positioned progressively by the actuator using the spindle and able to shut off the pipe, the overmoulding plastic material surrounding and being secured at least in part to the actuator and forming the pipe at least in part, the static sealing being afforded by overmoulding plastic material common to the actuator and the pipe, and the overmoulding material having passing through it a passage that is rendered fluid-tight for guiding the spindle that connects the valve shutter and the rotor.