A device for controlling a fuel-oxidizer mixture for a premix gas burner, comprising: - an intake duct, which defines a section for the admission of an oxidizer fluid into the duct and includes an inlet for receiving the oxidizer, a mixing zone for receiving the fuel and allowing it to be mixed with the oxidizer, and an outlet for delivering the mixture to the burner; - an injection duct, which defines a section for the admission of the fuel and which is connected to the intake duct in the mixing zone to supply the fuel; - a gas fuel regulating valve, located along the injection duct; - a fan, located in the intake duct to generate therein a flow of the oxidizer fluid or of the fuel-oxidizer mixture in a direction of inflow oriented from the inlet to the delivery outlet; - a control unit, configured for generating drive signals, for regulating the gas regulating valve and the rotation speed of the intake fan; - a sensor unit, in communication with the control unit and configured for detecting a first differential pressure, between a first detecting section, located in the intake duct upstream of the mixing zone in the direction of inflow and a second detecting section, located in the intake duct downstream of the mixing zone in the direction of inflow, and a second differential pressure, between the first detecting section and a third detecting section, located in the injection duct between the gas regulating valve and the mixing zone, wherein the first and the second differential pressure (P1, P2) are used by the control unit for regulating the speed of the fan and/or the opening of the fuel flow regulating valve to obtain a predetermined mixture. - an intake duct, which defines a section for the admission of an oxidizer fluid into the duct and includes an inlet for receiving the oxidizer, a mixing zone for receiving the fuel and allowing it to be mixed with the oxidizer, and an outlet for delivering the mixture to the burner; - an injection duct, which defines a section for the admission of the fuel and which is connected to the intake duct in the mixing zone to supply the fuel; - a gas fuel regulating valve, located along the injection duct; - a fan, located in the intake duct to generate therein a flow of the oxidizer fluid or of the fuel-oxidizer mixture in a direction of inflow oriented from the inlet to the delivery outlet; - a control unit, configured for generating drive signals, for regulating the gas regulating valve and the rotation speed of the intake fan; - a sensor unit, in communication with the control unit and configured for detecting a first differential pressure, between a first detecting section, located in the intake duct upstream of the mixing zone in the direction of inflow and a second detecting section, located in the intake duct downstream of the mixing zone in the direction of inflow, and a second differential pressure, between the first detecting section and a third detecting section, located in the injection duct between the gas regulating valve and the mixing zone, wherein the first and the second differential pressure (P1, P2) are used by the control unit for regulating the speed of the fan and/or the opening of the fuel flow regulating valve to obtain a predetermined mixture. a first differential pressure, between a first detecting section, located in the intake duct upstream of the mixing zone in the direction of inflow and a second detecting section, located in the intake duct downstream of the mixing zone in the direction of inflow, and a second differential pressure, between the first detecting section and a third detecting section, located in the injection duct between the gas regulating valve and the mixing zone, wherein the first and the second differential pressure (P1, P2) are used by the control unit for regulating the speed of the fan and/or the opening of the fuel flow regulating valve to obtain a predetermined mixture.