An analysis device configured to irradiate light onto a cell into which a sample has been introduced, to detect light that is transmitted through the cell, and to analyze measurement target components contained within the sample, comprising: a plurality of light sources including at least a first light source, a second light source, and a third light source; and an optical system that guides light from the respective light sources onto the cell, wherein the plurality of light sources each outputs light at a mutually different timing, and the optical system comprises: a first light source reflection mirror that reflects the light from the first light source; a second light source optical element that reflects the light from the first light source that has been reflected by the first light source reflection mirror and transmits the light from the second light source; a second light source reflection mirror that reflects the light from the first light source that has been reflected by the second light source optical element and the light from the second light source that has been transmitted through the second light source optical element; and a third light source optical element that reflects the light from the first light source and the light from the second light source that have been reflected by the second light source reflection mirror, and transmits the light from the third light source. a plurality of light sources including at least a first light source, a second light source, and a third light source; and an optical system that guides light from the respective light sources onto the cell, wherein the plurality of light sources each outputs light at a mutually different timing, and the optical system comprises: a first light source reflection mirror that reflects the light from the first light source; a second light source optical element that reflects the light from the first light source that has been reflected by the first light source reflection mirror and transmits the light from the second light source; a second light source reflection mirror that reflects the light from the first light source that has been reflected by the second light source optical element and the light from the second light source that has been transmitted through the second light source optical element; and a third light source optical element that reflects the light from the first light source and the light from the second light source that have been reflected by the second light source reflection mirror, and transmits the light from the third light source. a first light source reflection mirror that reflects the light from the first light source; a second light source optical element that reflects the light from the first light source that has been reflected by the first light source reflection mirror and transmits the light from the second light source; a second light source reflection mirror that reflects the light from the first light source that has been reflected by the second light source optical element and the light from the second light source that has been transmitted through the second light source optical element; and a third light source optical element that reflects the light from the first light source and the light from the second light source that have been reflected by the second light source reflection mirror, and transmits the light from the third light source.