A horizontal-axis wind turbine having a rotor with a hub and one or more blades, and a pitch control mechanism for driving and controlling a pitch angle of each of the blades independently; the hub and the blade are connected by an interposed section which can freely rotate around the pitch axis of the blade with respect to both the hub and the blade; and the pitch control mechanism includes: a hub-side interposed section drive unit that relatively rotates the interposed section with respect to the hub, and a blade-side interposed section drive unit that relatively rotates the blade with respect to the interposed section; the horizontal-axis wind turbine further comprising: a pitch control unit for controlling the pitch control mechanism, the control pitch unit being configured to control an angle of the blade around the pitch axis with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit for one blade; the horizontal-axis wind turbine characterized by further having: a hub-side interposed section angle sensor that detects an angle of the interposed section around the pitch axis with respect to the hub; a blade-side interposed section angle sensor that detects an angle of the blade around the pitch axis with respect to the interposed section; and a hub-side blade angle sensor that directly detects an angle of the blade around the pitch axis with respect to the hub; wherein the pitch control unit is configured to control an angle of the blade around the pitch axis with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit, based on the detected value from the hub-side interposed section angle sensor and the detected value from the blade-side interposed section angle sensor, and the pitch control unit is configured to control the angle around the pitch axis of the blade with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit based on the detected value from the hub-side blade angle sensor. a hub-side interposed section drive unit that relatively rotates the interposed section with respect to the hub, and a blade-side interposed section drive unit that relatively rotates the blade with respect to the interposed section; a pitch control unit for controlling the pitch control mechanism, the control pitch unit being configured to control an angle of the blade around the pitch axis with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit for one blade; a hub-side interposed section angle sensor that detects an angle of the interposed section around the pitch axis with respect to the hub; a blade-side interposed section angle sensor that detects an angle of the blade around the pitch axis with respect to the interposed section; and a hub-side blade angle sensor that directly detects an angle of the blade around the pitch axis with respect to the hub; wherein the pitch control unit is configured to control an angle of the blade around the pitch axis with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit, based on the detected value from the hub-side interposed section angle sensor and the detected value from the blade-side interposed section angle sensor, and the pitch control unit is configured to control the angle around the pitch axis of the blade with respect to the hub whether controlling both or just one of the hub-side interposed section drive unit and blade-side interposed section drive unit based on the detected value from the hub-side blade angle sensor.