An internal pressure measuring jig for a cylindrical battery cell, of the present invention, comprises: a lower jig which has a form corresponding to a cylindrical battery cell, and has a temperature measuring part and a receiving groove in which the cylindrical battery cell is separably inserted; and an upper jig which discharges gas inside the cylindrical battery cell, has a pressure measuring part for measuring the pressure of the discharged gas, and is separably coupled to the lower jig so as to close off an opening part of the receiving groove.