An interconnect layer is formed on a lower face of a silicon wafer, a support substrate is adhered over a lower face of the interconnect layer, and a thickness reduction of the silicon wafer is performed from an upper face side. Next, a photodiode is formed in an upper face of the silicon wafer, and a microlens is formed at a position corresponding to the photodiode. An adhesive layer is formed on the silicon wafer in a region not covering the microlens, a low refractive index layer having a lower refractive index than the microlens is formed in a region covering the microlens, and a glass substrate is adhered to the silicon wafer by the adhesive layer. The support substrate is removed from the interconnect layer, and a solder ball is bonded to a lower face of the interconnect layer. Thereafter, a CMOS image sensor is manufactured by dicing the silicon wafer.