The laser module includes a QCL element, a diffraction grating unit including a movable diffraction grating, a first lens that transmits light emitted from an end surface of the QCL element and light returning from the movable diffraction grating to the QCL element, a second lens that transmits terahertz waves emitted from the QCL element, a first holder, and a package. The first holder has a support surface on which the QCL element is mounted and a side surface connected to the support surface and facing the first lens in a resonance direction. A distance from an intersection point between the side surface and the support surface to the end surface along the resonance direction is smaller than a distance between the intersection point and the first lens along the resonance direction.