<p>A battery pack (10) includes: a battery (1); a circuit substrate (5) having a charge/discharge safety circuit and arranged on one end face (3) of the battery; and an end case (6) in which an external connection terminal (7) is set. In this battery pack, the circuit substrate (5) is arranged inside the end case (6), and the end case (6) is secured to the battery by screws (12) with a screw head (12a) extending through and engaging with the end case (6) at both ends and tips of the screw (12) being engaged into the end face (3) at both ends of the battery (1) . This achieves a compact battery pack with a reduced connection resistance, while achieving both high reliability and productivity.</p>
