An imaging lens assembly, having an optical axis and comprising at least one lens element (120, 130, 140), and the lens element (120, 130, 140) characterized in comprising: an optical effective region (121, 131, 141), the optical axis passing through the optical effective region (121, 131, 141); and a peripheral portion surrounding the optical effective region (121, 131, 141), and the peripheral portion comprising: an object-side surface (1221, 1321, 1421) facing towards an object side; an image-side surface (1222, 1322, 1422) facing towards an image side and corresponding to the object-side surface (1221, 1321, 1421); a peripheral surface (1223, 1323, 1423) connecting the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422); an annular marking structure (1224, 1324, 1424) disposed on one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the annular marking structure (1224, 1324, 1424) being an annular tip-ended protruding structure and surrounding the optical axis; and at least one arc portion (1225, 1226, 1325, 1326, 1425, 1426) disposed on the other one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the arc portion (1225, 1226, 1325, 1326, 1425, 1426) being an annular protruding arc; wherein a perpendicular distance between the annular marking structure (1224, 1324, 1424) and the optical axis is dm, a perpendicular distance between the arc portion (1225, 1325, 1425) and the optical axis is da, a curvature radius of the arc portion (1225, 1226, 1325, 1326, 1425, 1426) is Ra, and the following conditions are satisfied: 0.82 < da / dm < 1.18; and 0.025 mm ≤ Ra ≤ 0.5 mm. an optical effective region (121, 131, 141), the optical axis passing through the optical effective region (121, 131, 141); and a peripheral portion surrounding the optical effective region (121, 131, 141), and the peripheral portion comprising: an object-side surface (1221, 1321, 1421) facing towards an object side; an image-side surface (1222, 1322, 1422) facing towards an image side and corresponding to the object-side surface (1221, 1321, 1421); a peripheral surface (1223, 1323, 1423) connecting the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422); an annular marking structure (1224, 1324, 1424) disposed on one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the annular marking structure (1224, 1324, 1424) being an annular tip-ended protruding structure and surrounding the optical axis; and at least one arc portion (1225, 1226, 1325, 1326, 1425, 1426) disposed on the other one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the arc portion (1225, 1226, 1325, 1326, 1425, 1426) being an annular protruding arc; an object-side surface (1221, 1321, 1421) facing towards an object side; an image-side surface (1222, 1322, 1422) facing towards an image side and corresponding to the object-side surface (1221, 1321, 1421); a peripheral surface (1223, 1323, 1423) connecting the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422); an annular marking structure (1224, 1324, 1424) disposed on one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the annular marking structure (1224, 1324, 1424) being an annular tip-ended protruding structure and surrounding the optical axis; and at least one arc portion (1225, 1226, 1325, 1326, 1425, 1426) disposed on the other one of the object-side surface (1221, 1321, 1421) and the image-side surface (1222, 1322, 1422), and the arc portion (1225, 1226, 1325, 1326, 1425, 1426) being an annular protruding arc; wherein a perpendicular distance between the annular marking structure (1224, 1324, 1424) and the optical axis is dm, a perpendicular distance between the arc portion (1225, 1325, 1425) and the optical axis is da, a curvature radius of the arc portion (1225, 1226, 1325, 1326, 1425, 1426) is Ra, and the following conditions are satisfied: 0.82 < da / dm < 1.18; and 0.025 mm ≤ Ra ≤ 0.5 mm.