Provided is a connection module that can prevent a detection wire from coming away from a branch line path that is formed as a narrow path with a simple configuration. A connection module includes: a busbar configured to connect electrode terminals of adjacent electricity storage elements to each other; an insulating protector configured to hold the busbar in an insulated manner; and a detection wire that is to be connected to the busbar. The insulating protector includes a main line path, and a branch line path that branches from the main line path, has a width narrower than the width of the main line path, and in which the detection wire 50 is to be routed. The branch line path includes a pair of opposing path walls, and an elastic retaining piece that is formed on at least one path wall of the pair of path walls.