The image catching lens comprises a forwarding barrel and a guider. The forwarding barrel has an outer surface and an inner surface, and comprises a forwarding groove group, wherein the forwarding groove group comprises a first forwarding groove formed on the outer surface of the forwarding barrel and a second forwarding groove formed along the first forwarding groove and toward the inner surface. The guider comprises a guiding group, wherein the guiding group comprises a protrusion disposed corresponding to the second forwarding groove.