A connection module includes bus bars connecting positive and negative electrode terminals of adjacent power storage elements, a first sheet member that is expandable, and second sheet members fixing each of the bus bars independently. Each of the bus bars includes a fitting portion extending from one edge of the plate member with respect to a width direction (an arrow Y-direction) and fitting in a fixing portion of each second sheet member. The first sheet member holds each second sheet member to which each of the bus bars is fixed, and the first sheet member is expandable at sections between adjacent second sheet members in a longitudinal direction of the first sheet member in a distance of a maximum value of tolerance ΔL max that is a total value of tolerances of an electrode pitch with respect to an arrangement direction in which the adjacent power storage elements are arranged.