A contact member includes first and second bent portions provided between a joining part to be joined to a first board and a contacting part to come into contact with a second board, a first contact part to come into contact with the second bent portion when the first bent portion is caused to bend by the pressing of the contacting part by the second board, a second contact part to come into contact with the first bent portion when the second bent portion is caused to bend by the pressing of the contacting part by the second board after the first contact part comes into contact with the second bent portion, and a third contact part to come into contact with the first board by the pressing of the contacting part by the second board after the second contact part comes into contact with the first bent portion.