The new apparatus is developed for experimental determination of electron energy and spatial distributions in dense medium-energy long-pulsed magnetically confined beams – typically, 10 A/cm2, 60 keV, 100 µs, 0.1 T. To provide most detailed and unambiguous information, direct electrostatic cut-off method is used for electron energy analysis. In combination with variation of the magnetic field in the analysis area, this method allows to determine both (axial and transverse) components of electron energy. Test experiments confirmed ~1% energy resolution being predicted from calculations, accounting for electrode shapes, space-charge effects and nonadiabatic energy transfer effects in varied magnetic field. Space and time resolution of the apparatus are determined by the input aperture size (~1 mm) and cut-off electric field pulse-length (~5-10 µs) respectively.