To provide a filter which has a higher opening ratio than a filter using a mesh and in which a moire pattern is hardly visible when the filter is disposed in front of an image device having square pixels.

In a transparent filter on which many linear conductive materials are arranged on the surface of a sheet body to be disposed in front of an image device having square pixels, the conductive materials having ≤50 μm line width are arranged in two directions with a pitch P1 and a pitch P2 on the sheet body. The opening ratio of the filter is ≥70%. The P1, P2 and the lengths W1 and W2 of the pixel in the image device along the vertical direction and the horizontal direction, respectively, satisfy the relation of n1 +0.35≤W1/P1≤n1+0.65 and n2+0.35≤W2/P2≤n2+0.65.