PROBLEM TO BE SOLVED: To provide an apparatus for generating active species which can be made compact, and an indoor unit of an air conditioner which includes the apparatus for generating active species.SOLUTION: The apparatus 30 for generating active species includes: a first rectangular electrode 32 on which a discharge needle 34 is arranged a second rectangular electrode 35 arranged so as to cross a discharge needle-arranged portion of the first rectangular electrode 32 in planar view two supporting parts 44a, 44b for supporting the first electrode 32 on both sides of the discharge needle 34 and two supporting parts 45a, 45b for supporting the second electrode 35 on both sides of the crossing portion thereof with the first electrode 32. The supporting parts 44a, 44b are arranged between two straight lines which pass the supporting parts 45a, 45b respectively and are orthogonal to a straight line connecting the supporting parts 45a, 45b in planar view. In the apparatus 30 for generating active species, a voltage is applied between the first electrode 32 and the second electrode 35 to generate active species.
