An apparatus for sensing a moving ball, for acquiring and analyzing an image of the moving ball to calculate spin of the moving ball, the apparatus comprising: - an image acquisition unit for acquiring consecutive images according to movement of a ball with a surface having a predetermined feature portion indicated thereon; - an image processing unit for extracting: ∘ a first feature portion as a feature portion of a ball portion on a first image as a preceding image of two consecutively acquired images, and ∘ a second feature portion as a feature portion of a ball portion on a second image as a subsequent image of the two consecutively acquired images; - a spin calculation unit for calculating a spin axis and spin amount according to movement of a ball from the first image to the second image, by selectively performing any one of forward operation analysis and inverse operation analysis for comparing and analyzing a result obtained by applying a trial spin axis and spin amount to the first feature portion and the second feature portion characterized in that the spin calculation unit comprises an operation mode selector for: - comparing a size or a number of pixels of the first feature portion with a size or a number of pixels of the second feature portion, and - determining whether spin is calculated using forward operation analysis or inverse operation analysis; wherein the forward operation analysis is used when the size or the number of pixels of the first feature portion is greater than the size or the number of pixels of the second feature portion; and wherein the inverse operation analysis is used when the size or the number of pixels of the first feature portion is smaller than the size or the number of pixels of the second feature portion. - an image acquisition unit for acquiring consecutive images according to movement of a ball with a surface having a predetermined feature portion indicated thereon; - an image processing unit for extracting: ∘ a first feature portion as a feature portion of a ball portion on a first image as a preceding image of two consecutively acquired images, and ∘ a second feature portion as a feature portion of a ball portion on a second image as a subsequent image of the two consecutively acquired images; ∘ a first feature portion as a feature portion of a ball portion on a first image as a preceding image of two consecutively acquired images, and ∘ a second feature portion as a feature portion of a ball portion on a second image as a subsequent image of the two consecutively acquired images; - a spin calculation unit for calculating a spin axis and spin amount according to movement of a ball from the first image to the second image, by selectively performing any one of forward operation analysis and inverse operation analysis for comparing and analyzing a result obtained by applying a trial spin axis and spin amount to the first feature portion and the second feature portion characterized in that the spin calculation unit comprises an operation mode selector for: - comparing a size or a number of pixels of the first feature portion with a size or a number of pixels of the second feature portion, and - determining whether spin is calculated using forward operation analysis or inverse operation analysis; - comparing a size or a number of pixels of the first feature portion with a size or a number of pixels of the second feature portion, and - determining whether spin is calculated using forward operation analysis or inverse operation analysis;