4. A layout method for an automatic layout apparatus, comprising: the connection information storage step of receiving connection information and storing the information in a connection information storage means; the selection/layout step of selecting/laying out an arbitrary transistor on the basis of the input connection information or information stored in said connection information storage means; the element extraction step of extracting an element to be connected; the first conditioning step of performing extraction of the connection information, condition determination of a connection strength, and layout candidate ordering on the basis of information about said element extracted and information stored in layout condition storage means, and storing results in a first extracted-element storage means; the first automatic selection step of automatically selecting a layout candidate on the basis of information in the first conditioning step or the information stored in said first extracted-element storage means; the first determination step of determining whether automatic selection has been performed in the first automatic selection step; the first selection step of selecting whether automatic selection or arbitrary selection is performed when a determination result in the first determination step indicates that automatic selection has not been performed; the step of returning a flow to the first automatic selection step of automatically selecting said layout candidate when a selection result in the first selection step indicates automatic selection; the step of returning the flow to the selection/layout step when the selection result in the first selection step indicates arbitrary selection; the first layout step of executing layout when automatic selection is determined in the first determination step to have been performed; the first layout determination step of determining whether all elements have been laid out; the second conditioning step of ending the layout when the determined result in the first layout determination step indicates that all said elements have been laid out, and performing extraction of connection information, condition determination of the connection strength, and layout candidate ordering, and storing results in second extracted-element storage means when the determination result in the first layout determination step indicates that all said elements have not been laid out; the second automatic selection step of automatically selecting a layout candidate on the basis of information in the second conditioning step and the information stored in said first extracted-element storage means; the second determination step of determining whether automatic selection has been performed in the second automatic selection step; the second selection step of selecting whether automatic selection or arbitrary selection is performed when a determination result in the second determination step indicates that automatic selection has not been performed; the step of returning the flow to the selection/layout step when arbitrary selection is selected in the second selection step; the layout candidate selection step of selecting whether the information stored in said first extracted-element storage means or the information stored in said second extracted-element storage means is used when automatic selection is selected in the second selection step; the step of returning the flow to the second automatic selection step when a selection result in the layout candidate selection step indicates that the information stored in said first extracted-element storage means is used; the third automatic selection step of automatically selecting a layout candidate on the basis of the information stored in said second extracted-element storage means when the information stored in said second extracted-element storage means is selected to be used in the layout candidate selection step; the third determination step of determining whether automatic selection has been performed in the third automatic selection step; the third selection step of selecting whether automatic selection or arbitrary selection is performed when determination in the third determination step indicates that automatic selection has not been performed; the step of returning the flow to the third automatic selection step when automatic selection is selected to be performed in the third selection step; the step of returning the flow to the selection/layout step when arbitrary selection is selected to be performed in the third selection step; the second layout step of executing layout when automatic selection is determined in the third determination step to have been performed, or when automatic selection is determined in the second determination step to have been performed; the second layout determination step of determining whether all elements have been laid out in the second layout step; the step of returning the flow to the second conditioning step when all said elements are determined in the second layout determination step not to have been laid out; and the step of ending layout when all said elements are determined in the second layout determination step to have been laid out.
6. A method according to claim 4, wherein the first conditioning step comprises the step of determining the connection strength by collating a connection relationship between a reference element and a certain element in the information stored in said first extracted-element storage means with definition condition information stored in said layout condition storage means, and selecting an element having the highest connection strength as a layout candidate element on the basis of a determination result.