A split gate type nonvolatile semiconductor memory device and a method of fabricating a split gate type nonvolatile semiconductor memory device are provided. A gate insulating layer and a floating-gate conductive layer are formed on a semiconductor substrate. A mask layer pattern is formed on the floating-gate conductive layer to define a first opening extending in a first direction. First sacrificial spacers having a predetermined width are formed on both sidewalls corresponding to the mask layer pattern. An inter-gate insulating layer is formed on the floating-gate conductive layer. The first sacrificial spacers are removed, and the floating-gate conductive layer is etched until the gate insulating layer is exposed. A tunneling insulating layer is formed on an exposed portion of the floating-gate conductive layer. A control-gate conductive layer is formed on a surface of the semiconductor substrate. Second sacrificial spacers having predetermined widths are formed on the control-gate conductive layer. A split control gate is formed in the first opening, by etching the exposed control-gate conductive layer. The remaining mask layer pattern and inter-gate insulating layer are etched until the floating-gate conductive layer is exposed. The exposed floating-gate conductive layer is etched to form a split floating gate in the first opening.