A laser device comprising: a light source unit provided with a laser element for emitting laser light by forming a laser resonator with an output mirror, the laser element having a rear end surface on which a reflective film is formed; an optical element for determining a wavelength of oscillation emitted from the laser element, on a basis of an angle of the laser light incident on the optical element, the optical element being disposed in an optical path of the laser light emitted from the light source unit, between said laser element and said output mirror; the output mirror configured to reflect a part of emission light emitted from the optical element toward the optical element; and angle-of-incidence changing means for changing an angle at which the light emitted from the light source unit is incident on the optical element, wherein the output mirror configured to allow another part of the light than the reflected light reflected toward the optical element, which is a part of the emitted light emitted from the optical element to pass therethrough and outputs the other part of the light to the outside of the laser device, the light source unit includes a first lens for refracting the light emitted from the laser element to emit parallel light, and the angle-of-incidence changing means includes a second lens having an incident surface whose area is larger than an emission area of the light emitted from the first lens, the second lens allowing the light emitted from the first lens to be incident on the incident surface to collect the light; and lens moving means (8, 31) configured to change the angle of the light incident on the incident surface by allowing the second lens to move to change an incident position, on the incident surface, of the light emitted from the first lens, characterized in that the laser device comprises an integral component unit in which the second lens, the optical element, and the output mirror are formed into one unit, and wherein the lens moving means (8, 31) are configured to allow the integral component unit to move in a perpendicular direction to a direction in which the output mirror outputs the light outside the laser device, by which the second lens is configured to move in a perpendicular direction to a direction in which the output mirror outputs a light outside the laser device, and the incident position changes. a light source unit provided with a laser element for emitting laser light by forming a laser resonator with an output mirror, the laser element having a rear end surface on which a reflective film is formed; an optical element for determining a wavelength of oscillation emitted from the laser element, on a basis of an angle of the laser light incident on the optical element, the optical element being disposed in an optical path of the laser light emitted from the light source unit, between said laser element and said output mirror; the output mirror configured to reflect a part of emission light emitted from the optical element toward the optical element; and angle-of-incidence changing means for changing an angle at which the light emitted from the light source unit is incident on the optical element, wherein the output mirror configured to allow another part of the light than the reflected light reflected toward the optical element, which is a part of the emitted light emitted from the optical element to pass therethrough and outputs the other part of the light to the outside of the laser device, the light source unit includes a first lens for refracting the light emitted from the laser element to emit parallel light, and the angle-of-incidence changing means includes a second lens having an incident surface whose area is larger than an emission area of the light emitted from the first lens, the second lens allowing the light emitted from the first lens to be incident on the incident surface to collect the light; and lens moving means (8, 31) configured to change the angle of the light incident on the incident surface by allowing the second lens to move to change an incident position, on the incident surface, of the light emitted from the first lens, characterized in that the laser device comprises an integral component unit in which the second lens, the optical element, and the output mirror are formed into one unit, and wherein the lens moving means (8, 31) are configured to allow the integral component unit to move in a perpendicular direction to a direction in which the output mirror outputs the light outside the laser device, by which the second lens is configured to move in a perpendicular direction to a direction in which the output mirror outputs a light outside the laser device, and the incident position changes.