A computer-implemented evaluation method of a spheroid (Sp1, Sp2, Sp3), which is an aggregation of cultured cells, for evaluating a collapse degree of the spheroid (Sp1, Sp2, Sp3) from an image obtained by imaging the spheroid (Sp1, Sp2, Sp3), wherein the collapse degree of the spheroid (Sp1, Sp2, Sp3) is related to a decline of a spheroid formation ability of the cultured cells, and the computer-implemented evaluation method comprises: specifying a spheroid region taken up by the spheroid (Sp1, Sp2, Sp3) out of the image including the spheroid (Sp1, Sp2, Sp3) and a surrounding region thereof; obtaining an average value of an optical density of the spheroid (Sp1, Sp2, Sp3) and a magnitude of a variation of the optical density in the spheroid (Sp1, Sp2, Sp3) from an image density of the spheroid region; obtaining a circularity (Cr) of the spheroid (Sp1, Sp2, Sp3) from a contour of the spheroid region; obtaining a sharpness (Sh) of the spheroid (Sp1, Sp2, Sp3) from the image densities of the spheroid (Sp1, Sp2, Sp3) and the surrounding region thereof; and obtaining the collapse degree of the spheroid (Sp1, Sp2, Sp3) by substituting the average value of the optical density, the magnitude of the variation of the optical density, the circularity (Cr) and the sharpness (Sh) into a predetermined operational expression, wherein the operational expression is determined by collecting a plurality of spheroid images having numerical values indicating the collapse degrees given thereto in advance depending on contents of the spheroid images and performing a regression analysis using the average value of the optical density, the magnitude of the variation of the optical density, the circularity (Cr) and the sharpness (Sh) of the spheroid (Sp1, Sp2, Sp3) obtained for each of the collected images as a cause system and numerical values of the collapse degrees of the images as a result system. specifying a spheroid region taken up by the spheroid (Sp1, Sp2, Sp3) out of the image including the spheroid (Sp1, Sp2, Sp3) and a surrounding region thereof; obtaining an average value of an optical density of the spheroid (Sp1, Sp2, Sp3) and a magnitude of a variation of the optical density in the spheroid (Sp1, Sp2, Sp3) from an image density of the spheroid region; obtaining a circularity (Cr) of the spheroid (Sp1, Sp2, Sp3) from a contour of the spheroid region; obtaining a sharpness (Sh) of the spheroid (Sp1, Sp2, Sp3) from the image densities of the spheroid (Sp1, Sp2, Sp3) and the surrounding region thereof; and obtaining the collapse degree of the spheroid (Sp1, Sp2, Sp3) by substituting the average value of the optical density, the magnitude of the variation of the optical density, the circularity (Cr) and the sharpness (Sh) into a predetermined operational expression, wherein the operational expression is determined by collecting a plurality of spheroid images having numerical values indicating the collapse degrees given thereto in advance depending on contents of the spheroid images and performing a regression analysis using the average value of the optical density, the magnitude of the variation of the optical density, the circularity (Cr) and the sharpness (Sh) of the spheroid (Sp1, Sp2, Sp3) obtained for each of the collected images as a cause system and numerical values of the collapse degrees of the images as a result system.