A clip unit includes: an arm portion including arms extending from a proximal end portion to a distal end portion so as to be openable and closeable; a holder than can hold the arms in a closed state by accommodating the proximal end portion of the arm portion; and a thread grip attached to at least one of the arms and positioned between the arms. In a state where the arms are spread open, a dimension of the thread grip in the opening/closing direction of the arms is equal to or larger than a distance between the arms in the closed state. The thread can be elastically deformed in the closed state.