Abstract: Provided is a sub-sampler used for taking a sub-sample from a core sample filled in a liner of a corer. The sub-sampler includes agitation preventing walls 100a, 100b and 100c including a top surface 10 having a predetermined length, a side surface 20 extended to be bent in a downward direction from one end of the top surface 10, and a contact surface 30 extended such that one end of the side surface meets the other end of the top surface 10; and a cut piece 200 that allows an arrangement gap between one agitation preventing wall 100a and any other agitation preventing wall 100b to be regular and that is connected to the side surface 20 in order to close one side surface of the arranged agitation preventing walls 100a, 100b and 100c.