In a cylindrical battery including a gap formed between a peripheral side surface 32b of a dish-shaped portion in an anode terminal plate 32 and a curved end portion 11a of a cathode can 11, and a washer 50 having a cylindrical boss portion 50a and an annular flange portion 50c provided around an upper end surface of the cylindrical boss portion 50athe washer 50 being mounted to an opening portion of a cathode can 11 such that the cylindrical boss portion 50a is fitted into the gap 201, a vent structure configured to release gas released to the gap 201 from a first vent hole 32c in the anode terminal plate 32 to an exterior of the cylindrical battery (1) from an arc-shaped second vent hole (50d) formed in the flange portion(50c) or an annular gap (301, 302) formed between the upper end surface of the cylindrical boss portion (50a) and the terminal plate(32).