The micro-sensor includes a first circuit substrate and a second circuit substrate. One surface of the first circuit substrate has an image sensing device electrically connected to main printed wires formed by a first wire group and a second wire group. On the other surface of the first circuit substrate has a main connector electrically connected to the second wire group. A plurality of first signal transmission lines connected to the first wire group. The second circuit substrate has a sub-connector that is electrically connected to sub printed wires having an equivalent number as and corresponding to the second wire group. The other end of the sub printed wires is electrically connected to a plurality of second signal transmission lines. Through connecting the connectors respectively disposed in different circuit boards to overcome the difficulty in the manufacturing process of concentrating all devices on a single circuit board.