A continuous method for synthesizing a diene elastomer includes modifying the diene elastomer in a functionalizing device by: a kinetic model according to which the ratio of the rate constants is greater than 1, and a flow represented by a residence time distribution in the functionalizing device that is expressed according to equations 1 or 3: (i) in a functionalizing device having at least one tubular continuous reactor or having at least one cascade of at least two stirred reactors, E 1 ⁡ ( t ) = 1 2 ⁢ ( P πθ 1 ⁢ t ) 1 2 ⁢ e - P ⁡ ( θ 1 - t ) 2 4 ⁢ θ 1 ⁢ t Eq ⁢ ⁢ 1 (ii) in a functionalizing device that is a combination of the device (i) and of a device having at least one continuous stirred reactor, having a residence time distribution characterized by the following equation: E 2 ⁡ ( t ) = e ( - t θ 2 ) θ 2 Eq ⁢ ⁢ 2 the device (ii) having a residence time distribution characterized by the equation 3 below, which is the result of the convolution of equations 1 and 2: E 12 ⁡ ( t ) = ∫ 0 t ⁢ E 1 ⁡ ( t - T ) ⁢ E 2 ⁡ ( T ) ⁢ ⁢ d ⁢ ⁢ T ⁢ ⁢ E 12 ⁡ ( t ) = ∫ 0 t ⁢ 1 2 ⁢ ( P πθ 1 ⁡ ( t - T ) ) 1 2 ⁢ e - P ⁡ ( θ 1 - ( t - T ) ) 2 4 ⁢ θ 1 ⁡ ( t - T ) ⁢ e ( - T θ 2 ) θ 2 ⁢ d ⁢ ⁢ T Eq ⁢ ⁢ 3