A battery module comprising: (a) a battery cell stack having a plurality of battery cells or unit modules connected in series and/or in parallel to each other in a state in which the battery cells or the unit modules are stacked in the lateral direction, the battery cell stack being provided at the front thereof with bus bars to connect electrode terminals of the battery cells to external input and output terminals; (b) voltage sensing members provided at ends thereof with connection terminals electrically connected to electrode terminal connection parts of the battery cells disposed at the front and rear of the battery cell stack to sense voltages of the battery cells or the unit modules; (c) an upper case to cover the end of one side of the battery cell stack and portions of the top and bottom of the battery cell stack, the upper case being provided with mounting parts, in which the voltage sensing members are mounted; and (d) a lower case coupled to the upper case in a state in which the lower case covers the end of the other side of the battery cell stack and portions of the top and bottom of the battery cell stack, the lower case being provided at the front thereof with external input and output terminals, characterized in that the voltage sensing members comprise a front sensing member connected to the electrode terminal connection parts disposed at the front of the battery cell stack and a rear sensing member connected to the electrode terminal connection parts disposed at the rear of the battery cell stack, and the front sensing member and the rear sensing member comprise main bodies, each of which is formed in the shape of a connector having a hollow structure, and connection terminals connected to series-connection bent regions (electrode terminal connection parts) of the electrode terminals of the battery cells in a state in which the connection terminals are fitted in the respective main bodies, respectively. (a) a battery cell stack having a plurality of battery cells or unit modules connected in series and/or in parallel to each other in a state in which the battery cells or the unit modules are stacked in the lateral direction, the battery cell stack being provided at the front thereof with bus bars to connect electrode terminals of the battery cells to external input and output terminals; (b) voltage sensing members provided at ends thereof with connection terminals electrically connected to electrode terminal connection parts of the battery cells disposed at the front and rear of the battery cell stack to sense voltages of the battery cells or the unit modules; (c) an upper case to cover the end of one side of the battery cell stack and portions of the top and bottom of the battery cell stack, the upper case being provided with mounting parts, in which the voltage sensing members are mounted; and (d) a lower case coupled to the upper case in a state in which the lower case covers the end of the other side of the battery cell stack and portions of the top and bottom of the battery cell stack, the lower case being provided at the front thereof with external input and output terminals, characterized in that the voltage sensing members comprise a front sensing member connected to the electrode terminal connection parts disposed at the front of the battery cell stack and a rear sensing member connected to the electrode terminal connection parts disposed at the rear of the battery cell stack, and the front sensing member and the rear sensing member comprise main bodies, each of which is formed in the shape of a connector having a hollow structure, and connection terminals connected to series-connection bent regions (electrode terminal connection parts) of the electrode terminals of the battery cells in a state in which the connection terminals are fitted in the respective main bodies, respectively.