With the optimal choice of a target and the laser pulse parameters, the ultrahigh current density of the protons ejected from the target (over 10 ¹⁰ A cm^-2) is experimentally shown to be achievable already for a laser intensity of ∼ 2 × 10¹⁷ W cm ^-2 (the pulse energy is less than 1 J and its duration does not exceed 1 ps). Table-top laser systems with such parameters are promising as ion sources for applications in nuclear physics, medicine, ion implantation, and material diagnostics.