The project for a superconducting electron cyclotron resonance (ECR) ion source has been funded by INFN in 1992 as a joint venture between INFN and CEA/DRFMC. The source is devoted to the production of high charge state heavy ions to be injected into the K‐800 superconducting cyclotron. The magnetic system consists of three solenoids and of an hexapole which will allow one to attain a strong plasma confinement by means of aB‐min field configuration with a very high magnetic field (1.4 T on the plasma chamber wall). At the intermediate frequency of 14.5 GHz, it will be possible to study the scaling of ECR ion sources at different magnetic fields far beyond the existing levels. The source will eventually work at a higher frequency, in the range 28–35 GHz of gyrotron tubes. The design of the superconducting magnets and of the cryostat has been carefully carried out, taking into account this goal, and the construction is now under course. The mechanical design of the plasma chamber is also outlined.