PURPOSE: To reduce measuring time by simultaneous measurement of MTF and measurement of projecting resolving power by forming the image of an object by the images of slits and a grating shape and disposing solid state image sensing elements having linear photodetecting areas in the direction intersecting orthogonally with the slit images by the slits on a projecting plane.

CONSTITUTION: An object 2 has slits Sv, Sh and a grating-like image K. The slits Sv, Sh are used for measurement of MTF. The grating-like image K is used for measurement of projecting resolving power. The object images are magnified and are projected on a projecting plane 4. The slit images of the slits Sv, Sh are formed on the photodetecing areas 7a, 8a of S'v, S'h solid image sensing devices 7, 8 and the image of the grating-like image K is formed on the grating image projecting plane 9 having an area of p.m×Q.m size in which the image is included, respectively. The projected images of the slit images are formed on the devices 7, 8 and when the distributions of the light intensity of said images are electrically Fourier-transformed, MTF is determined. At the same time the grating-like image projected on the plane 9 is observed, whereby the measurement of the projecting resolving power is made possible.