A resolver signal processing device comprising: an excitation-signal transmitting portion for transmitting an excitation signal including a sine wave to a resolver; and a calculation portion for detecting extremes of a sine wave output signal and a cosine wave output signal from the resolver and detecting a rotational angle of the resolver based on of the extremes, wherein the excitation-signal transmitting portion includes: a storage portion for storing sine wave data for two cycles, and a DMA transfer portion for performing DMA transfer of the sine wave data for one cycle from a phase specified in the storage portion as the excitation signal to the resolver, and the calculation portion being adapted to command the DMA transfer portion to perform DMA transfer of the excitation signal from a reference phase, and detect a phase difference between the excitation signal and the sine wave output signal or the cosine wave output signal, in initial setting prior to operating the resolver; and command the DMA transfer portion to perform DMA transfer of the excitation signal from a modified phase set forward for the phase difference with respect to the reference phase, and detect the rotational angle based on the extremes, in detecting the rotational angle immediately after the initial setting. an excitation-signal transmitting portion for transmitting an excitation signal including a sine wave to a resolver; and a calculation portion for detecting extremes of a sine wave output signal and a cosine wave output signal from the resolver and detecting a rotational angle of the resolver based on of the extremes, wherein the excitation-signal transmitting portion includes: a storage portion for storing sine wave data for two cycles, and a DMA transfer portion for performing DMA transfer of the sine wave data for one cycle from a phase specified in the storage portion as the excitation signal to the resolver, and the calculation portion being adapted to command the DMA transfer portion to perform DMA transfer of the excitation signal from a reference phase, and detect a phase difference between the excitation signal and the sine wave output signal or the cosine wave output signal, in initial setting prior to operating the resolver; and command the DMA transfer portion to perform DMA transfer of the excitation signal from a modified phase set forward for the phase difference with respect to the reference phase, and detect the rotational angle based on the extremes, in detecting the rotational angle immediately after the initial setting. a storage portion for storing sine wave data for two cycles, and a DMA transfer portion for performing DMA transfer of the sine wave data for one cycle from a phase specified in the storage portion as the excitation signal to the resolver, and the calculation portion being adapted to command the DMA transfer portion to perform DMA transfer of the excitation signal from a reference phase, and detect a phase difference between the excitation signal and the sine wave output signal or the cosine wave output signal, in initial setting prior to operating the resolver; and command the DMA transfer portion to perform DMA transfer of the excitation signal from a modified phase set forward for the phase difference with respect to the reference phase, and detect the rotational angle based on the extremes, in detecting the rotational angle immediately after the initial setting.