This paper reports on the variation of the physical properties of vacuum breakdown in microgaps from the static to the pulsed electric fields in a quasi-homogeneous electric field. The measurements were performed between the spherical cathode and planar anode, both made of stainless-steel separated from 1 μm up to 10 μm at the pressure of ∼1×10−4 Pa. Pulse rise time was varied gradually from fast 1011 V/s down to 3 V/s. Several stages during pre-breakdown have been distinguished dependent on the pulse rise time from the recorded current–voltage characteristics. A detailed analysis of each pre-breakdown stage was based on the field emission theory. From the Fowler–Nordheim plots, the enhancement factor, the radius of the emitting area, and the maximum current density were calculated and subsequently substituted to the General Thermal-Field emission equation to estimate the dominating mechanism of the electron emission.