In a connection module attached to a single battery group from a first direction, a detection terminal connected to an electrode terminal of the single battery group includes: a body portion made of a metal plate material formed in an approximately rectangular plate shape; and a projection portion in a plate shape connected to a base edge of the body portion and having a plate surface intersecting with a plate surface of the body portion. An insulation protector of the connection module includes a holding portion holding the detection terminal in a posture in which the plate surface of the body portion is orthogonal to the first direction. The holding portion includes a locking piece. A lower surface of a claw portion provided at the lower end of the locking piece locks the plate surface of the body portion and restricts the movement of the detection terminal in the first direction.