To provide a solid state image sensing element wherein S/N ratio of a signal acquired by electron multiplication with no mixture of noise can be improved by selecting to carry out electron multiplication by external manipulation, and to provide a method for driving it.

In the solid state image sensing element 36, transfer electrodes 42 and 44 in readout of signal charges are divided into transfer electrodes 42a and 44a for transferring the signal charge and transfer electrodes 42b and 44b for reading out the signal charge from a photodetecting element 38. Gradient of potential formed right under the transfer electrodes 42b and 44b is made steep to contribute to electron multiplication.