Objective To investigate the fire patterns of the primary cultured postnatal mouse spiral ganglion neurons.Methods Current-clamp recordings with the use of the whole cell configuration of the patch-clamp technique were made from the primary cultured spiral ganglion neurons. Results The action potential was recorded from the spiral ganglion neurons. The neurons had non-uniform firing characteristics. Conclusion There were two firing patterns observed in the spiral ganglion neurons, rapid adaptation, and slow adaptation and the largest neurons showing rapidly adapting.