A tunnel current control apparatus includes a terahertz wave generation element configured to generate and output a terahertz wave pulse, a CEP adjustment unit configured to adjust a CEP of the terahertz wave pulse, and an off-axis parabolic mirror serving as a focusing element configured to focus the terahertz wave pulse in a gap between a first conductive object and a second conductive object. The CEP adjustment unit can arbitrarily adjust the CEP of the terahertz wave pulse.