<p>Disclosed is a webbing winding device in which a clutch mechanism positioned between the output shaft of a motor and a spool operates in an improved manner, and in which the structure of the clutch mechanism is simplified. An interference piece (140) whereof an interference part (152) interferes with a coupling pawl when the input gear of a clutch rotates in the direction of winding is inserted between an outer-side retaining ring (146) and an inner-side retaining ring (148) whereof a base part (142) is formed in a gear box (52), and the base part (142) is connected by pressure to the inner peripheral part of the outer-side retaining ring (146) and outer peripheral part of the inner-side retaining ring (148). The interference part (152) continues to interfere with the coupling pawl until a pressing force exceeding the maximum static friction force between the inner peripheral part of the outer-side retaining ring (146) and outer peripheral part of the inner-side retaining ring (148) and the base part (142) is applied to the interference part (152) by the coupling pawl, thereby causing the coupling pawl to pivot.</p>
