A cooling jacket for cooling a battery cell, according to the present invention, has a cooling plate having a board shape and a plurality of cooling channels provided inside the cooling plate, and makes close contact with one surface of a battery cell so as to absorb heat generated by the battery cell, wherein the plurality of cooling channels include: a coolant supply manifold channel and a coolant discharge manifold channel, which are disposed one-by-one at both sides of the cooling plate, and extend toward the outside from the inside of the cooling plate such that one end of each of the coolant supply manifold channel and the coolant discharge manifold channel are exposed toward the outside; and non-uniform cooling channels disposed to be spaced apart from each other at predetermined intervals, having both ends connected to the coolant supply manifold channel and the coolant discharge manifold channel across the cooling plate, and having a non-uniformly formed width.