A light irradiating device used for curing and a manufacturing method of a wire module comprising a wiring part are provided. The light irradiating device aims to enable a light curing agent attached to the periphery of a processing object part of a wire to be cured more reliably. The light irradiating device used for curing comprises: a light irradiating part (110); a rotation support mechanism (120) for enabling the light irradiating part (110) to be rotatably supported around a processing object part of the wire (22), i.e., a wiring part, in the case of enabling a light from the light irradiating part (110) to irradiate towards the processing object part of the wire supported at a curing processing position P; and a rotation driving mechanism (130) for enabling the rotation support mechanism (120) to rotate. And preferredly, the plurality of light irradiating parts (110) are rotatably supported around the processing object part of the wire, and rotate at a rotating angle within the range less than 360 degr
