Distortion of the temperature control element and the package by thermal deformation or mechanical deformation is prevented from being transmitted to the optical element as stress, and at the same time, constant temperature control of the optical element is realized. An optical element unit including an optical element that requires temperature control and an optical component that does not require temperature control, and a temperature control element for performing temperature adjustment of the optical element are arranged. The temperature control element performs temperature adjustment control of the optical element through a region mounted with the optical component of the optical element unit.