A method for manufacturing a solid state imaging device includes steps of forming a photodiode layer buried in a semiconductor substrate by ion injection and of forming a shielding layer buried in the photodiode layer by ion injection. At least in the ion injection process in the step of forming the shielding layer, an ion injection pause period is provided at least one time during whole ion injection step. According to the method, crystal defects are prevented from generating even if ion injection is performed with high energy, thereby suppressing dark current without complexity in manufacturing process.