With this semiconductor device, the distortion and cracking of a thinned portion of a semiconductor substrate are prevented to enable high precision focusing with respect to a photodetecting unit and uniformity and stability of high sensitivity of the photodetecting unit to be maintained. A semiconductor device 1 has a semiconductor substrate 10, a wiring substrate 20, conductive bumps 30, and a resin 32. A CCD 12 and a thinned portion 14 are formed on semiconductor substrate 10. Electrodes 16 of semiconductor substrate 10 are connected via conductive bumps 30 to electrodes 22 of wiring substrate 20. Wiring substrate 20 has formed therein a groove portion 26a that surrounds a region opposing thinned portion 14 and groove portions 26b that extend to an exposed surface of wiring substrate 20 from groove portion 26a. Insulating resin 32 fills a gap between outer edge 15 of thinned portion 14 and wiring substrate 20 to reinforce the bonding strengths of conductive bumps 30.