A connection module includes a first bus bar, a second bus bar and a connection unit. The connection unit includes a housing case having an insulation property and having a housing space formed therein, and a fastening member disposed inside the housing space. The connection unit is provided with a tool insertion hole through which a tool to be attached to the fastening member is insertable. The fastening member is configured to electrically connect the first bus bar and the second bus bar that are disposed inside the housing space. An insulation member is disposed in a portion of the fastening member that is visible through the tool insertion hole when the fastening member is seen through the tool insertion hole.