The optical module comprises a device mounted with a photoelectric element and a receptacle to optically connect this device and an optical fiber is provided. The receptacle comprises a device holder at its one end, allows the device holder to be fitted to the top end side of the device, and fixed and held through the interposition of the ultraviolet curing resin. The device holder comprises a window area relatively large in an amount of ultraviolet transmission dispersedly arranged on the entire periphery of the fitted portion with the device.