PURPOSE: To obtain a semiconductor laser cap capable of reducing the manufacturing manpower and hence simplifying the manufacturing process by allowing an entire body to comprise a transparent material and form a diffraction grating pattern for hologram on the surface.

CONSTITUTION: An entire body comprises a transparent body (for example, plastics) and a diffraction grating pattern 2 for hologram is formed on the surface. A cap 1 based on this structure is one piece molded, including the diffraction pattern 2. Therefore, there is no need for boring a round hole for light injection and bonding a glass disk to shut-down the open air on the peripheral edge. It is capable of isolating a semiconductor laser chip from the open air by simply connecting the disk with a stem as it is. Furthermore, this one piece molding makes it possible to curtail manufacturing manpower greatly and hence reduce cost sharply.