Electric vaporiser for a fragranced or insecticidal active substance with adjustment of the evaporation intensity, includes a support technical body, onto which a porous element impregnated with the active substance and an electric heating device located in the proximity of the porous element are fixed, in order to determine the evaporation of the active substance in an evaporation area. The electric heating device is housed in a drawer which is movable in a direction substantially perpendicular to the porous element, between a position of maximum evaporation intensity, near or adjacent to the porous element, and a position of minimum evaporation intensity, far from the porous element. The control mechanism which causes the shifting of the electrical device includes a variable-radius cam obtained in an adjustment disc, with which a pin integral with the drawer and protruding therefrom engages; the mechanism is located entirely outside the evaporation area.