A temperature control device comprising: a first light source unit (11B, 110B); a second light source unit (11G, 110G), a temperature control effort for which is different from a temperature control effort for the first light source unit (11B, 110B); a heat exchanger plate (121, 122) in contact with the first light source unit (11B, 110B) and the second light source unit (11G, 110G); a single temperature control element configured to control temperature of the first light source unit (11B, 110B) and temperature of the second light source unit (11G, 110G) via the heat exchanger plate; a thermal resistance adjustment part (131, 132) configured to adjust at least one of a value of a thermal resistance between the temperature control element and the first light source unit (11B, 110B) and a value of a thermal resistance between the temperature control element and the second light source unit (11G, 110G); and a third light source unit (11R, 110R), wherein the temperature control effort for the first light source unit (11B, 110B) is less than any of the temperature control effort for the second light source unit (11G, 110G) and a temperature control effort for the third light source unit (11R, 110R), and wherein the value of the thermal resistance between the temperature control element and the first light source unit (11B, 110B) is adjusted by the thermal resistance adjustment part (131, 132) to be greater than any of a value of the thermal resistance between the temperature control element and the second light source unit (11G, 110G) and a value of a thermal resistance between the temperature control element and the third light source unit (11R, 110R), characterized in that the heat exchanger plate has a shape of a letter L, wherein the first light source unit (11B, 110B) is in contact with an inside of a short side of the letter L of the heat exchanger plate, wherein the second light source unit (11G, 110G) and the third light source unit (11R, 110R) are in contact with an inside of a long side of the letter L of the heat exchanger plate, and wherein the temperature control element is in contact with an outside of the long side of the letter L of the heat exchanger plate. a first light source unit (11B, 110B); a second light source unit (11G, 110G), a temperature control effort for which is different from a temperature control effort for the first light source unit (11B, 110B); a heat exchanger plate (121, 122) in contact with the first light source unit (11B, 110B) and the second light source unit (11G, 110G); a single temperature control element configured to control temperature of the first light source unit (11B, 110B) and temperature of the second light source unit (11G, 110G) via the heat exchanger plate; a thermal resistance adjustment part (131, 132) configured to adjust at least one of a value of a thermal resistance between the temperature control element and the first light source unit (11B, 110B) and a value of a thermal resistance between the temperature control element and the second light source unit (11G, 110G); and a third light source unit (11R, 110R), wherein the temperature control effort for the first light source unit (11B, 110B) is less than any of the temperature control effort for the second light source unit (11G, 110G) and a temperature control effort for the third light source unit (11R, 110R), and wherein the value of the thermal resistance between the temperature control element and the first light source unit (11B, 110B) is adjusted by the thermal resistance adjustment part (131, 132) to be greater than any of a value of the thermal resistance between the temperature control element and the second light source unit (11G, 110G) and a value of a thermal resistance between the temperature control element and the third light source unit (11R, 110R), characterized in that the heat exchanger plate has a shape of a letter L, wherein the first light source unit (11B, 110B) is in contact with an inside of a short side of the letter L of the heat exchanger plate, wherein the second light source unit (11G, 110G) and the third light source unit (11R, 110R) are in contact with an inside of a long side of the letter L of the heat exchanger plate, and wherein the temperature control element is in contact with an outside of the long side of the letter L of the heat exchanger plate.