A connector manufacturing method includes: a first insertion process of inserting a conductor held by a housing through an annular seal member; a second insertion process of inserting the conductor through an annular portion of a support member; a pushing-in process of pushing the seal member into a gap between an inner circumferential surface of a recess in the housing and the conductor by pressing the seal member using the annular portion; and an engagement process of making the annular portion support the seal member at a predetermined position by engaging the support member and the housing, wherein the predetermined position is a position before a bottom portion of the recess.