A micro-lens built-in vertical cavity surface emitting laser (VCSEL). The micro-lens built-in VSEL includes a VCSEL portion emitting a laser beam in a direction in which semiconductor material layers are stacked; a micro-lens formed of a material capable of transmitting the laser beam emitted from the VCSEL portion; and an adjusting portion located between the VCSEL portion and the micro-lens adjusting a distance between the micro-lens and the VCSEL portion. When constructing an optical system with the VCSEL including the VCSEL portion, the adjusting portion, and the micro-lens, there is no need for a separate condensing lens and focusing position adjusting element. In addition, optical alignment structure is simple with increased freedom in arranging elements, and the number of parts required is sharply reduced.