Cross flow fan, and air conditioner fitted with the same, the cross flow fan including a plurality of annular rims arranged at regular intervals along a horizontal direction, and a plurality of blades on a side surface of the rim vertical thereto, and along a circumference direction of the rim, wherein pitch angles between two adjacent blades are not regular, the pitch angle taking a center of the rim as an apex, and a number of blades are 32 or 35. The pitch angles of the blades are designed by a computer optimization method taking a number of the blades and the like as parameters.