Abstract: A resolver (100) used for a rotational angle detecting device is provided with a stator (200) which is formed with a plurality of annularly-linked stator teeth (210) and a rotor (300) which is rotatably provided with respect to the stator (200). A group of output windings which have output windings connected in series in order to obtain an output signal corresponding to the rotational angle of the rotor (300) are wound about the stator teeth (210). When a number is assigned to each stator tooth (210) in accordance with the order of placement of the stator tooth (210), the number of windings W(k) of the output windings wound about the k-th stator tooth (210) is defined by the following formula (1). Thus, with respect to methods of detecting a rotational angle or winding synchronizing device windings in order to output a sinusoidal signal from the group of output windings, the number of windings can be easily set compared to in the past.