A forming-free SiN-based resistive switching memory (RSM) device has been successfully realized using an RF sputtering method. With a 10-nm thick SiN film, the memory device showed forming-free switching behavior under ±2 V/100 ns. The conduction mechanisms at low- and high-resistance states were verified by Ohmic behavior and modified space-charge-limited conduction, respectively. In a reliability test, the device exhibits good endurance over 109 cycles and long data retention over 105 s at 85 °C. These results demonstrate that SiN-based RSM devices can be readily available without forming processes using an RF sputtering method.