To provide an evaluation mask for evaluating by detecting the mask deformation of a thin membrane mask and deformation of a transfer pattern.

The evaluating mask 10 comprises four square unit scanning regions 14a to 14d, having the same size on a circular Si mask base 12, having the same material and thickness as those of a copy mask to be evaluated. The regions 14a and 14b have a long rectangular pattern opening 16 formed substantially at the center, and 39 small opening positional deviation measuring marks 18 disposed in a lattice shape at equal intervals in the lateral an longitudinal directions around the pattern opening 16. The opening 16 is formed in the same shape, size and structure as those of the copy mask. The regions 14c and 14d have a planar region 19 having no pattern opening instead of the pattern region having the pattern opening 16, and have 39 positional deviation reference marks 20, disposed in a lattice shape at the intervals in the lateral and longitudinal directions, so as to be superposed on the positional deviation pattern, when the region 14c is superposed on the region 14a and the region 14d is superposed on the region 14b.