A miniaturized device for measurements of very low level pressure, comprising: - an ionization-based detection member, configured to detect a pressure value (P 1) and to generate an electrical signal (S 1) representative of said pressure value (P 1); - electronic processing means, operatively connected to said ionization-based detection member, and configured to generate a measured pressure value based on said electrical signal (S 1); - interface means, operatively connected to said electronic processing means and configured to provide in output said measured pressure value, wherein said ionization-based detection member, electronic processing means, and interface means are comprised in a single integrated device, and wherein the ionization-based detection member comprises: - at least one ionization source; - an ionization region, containing gas particles the pressure of which has to be measured, arranged so as to be passed through by ionization electrons generated by said source, so that the ionization electrons ionize the gas particles, thus generating respective ions; - ion extraction means, configured to determine a preferential trajectory for the generated ions, passing through at least one ion extracting window, through which the ions leave the ionization region; - at least one ion detector, configured to detect ions and generate said electrical signal (S 1) depending on the amount of ions detected and representative of the pressure value of the gas particles that are present in the ionization region, the device being characterized in that said at least one ion detector has micrometric dimensions and comprises a ion impact surface having an area of less than one mm 2, and said at least one ion detector is arranged at said respective at least one ion extraction window, so as to be shielded against trajectories of X rays generated by impacts of the ionizing electrons with parts of the ionization region other than the at least one ion detector. - an ionization-based detection member, configured to detect a pressure value (P 1) and to generate an electrical signal (S 1) representative of said pressure value (P 1); - electronic processing means, operatively connected to said ionization-based detection member, and configured to generate a measured pressure value based on said electrical signal (S 1); - interface means, operatively connected to said electronic processing means and configured to provide in output said measured pressure value, - at least one ionization source; - an ionization region, containing gas particles the pressure of which has to be measured, arranged so as to be passed through by ionization electrons generated by said source, so that the ionization electrons ionize the gas particles, thus generating respective ions; - ion extraction means, configured to determine a preferential trajectory for the generated ions, passing through at least one ion extracting window, through which the ions leave the ionization region; - at least one ion detector, configured to detect ions and generate said electrical signal (S 1) depending on the amount of ions detected and representative of the pressure value of the gas particles that are present in the ionization region,