A guide mechanism for a connecting component guides a second connecting component when connecting a first connecting component and the second connecting component to each other. The guide mechanism includes a guide member and an urging member. The urging member urges the guide member and continues to contract until the second connecting component reaches a connection complete position. The guide member includes rotational shafts, inner guide pieces, and outer guide pieces. The rotational shafts are provided on both sides of the second connecting component. The inner guide pieces are rotated about the rotational shafts from first initial positions to first regulating positions. The outer guide pieces are rotated about the rotational shafts from second initial positions to second regulating positions such that the rotation of the outer guide pieces is coupled with the rotation of the inner guide pieces.