58 a being positioned inside the cam part 54 viewing as a plane and being capable of coupling with the trace part 50 b is formed for example it also may be crescent shaped also here the trace member 50 was formed with metal but it is not absolutely necessary to be metal furthermore in this mode a latch device 10 having a latch body 16 inserted inside a housing 12 and is forced toward the pulling out direction is attached to the attachment member 24 however the latch device 10 may in other embodiments be attached to the receiving body 60 and the striker 66 may be attached to the attachment member 24 furthermore although one embodiment of the lock mechanism may comprise a circulating cam groove 56 and a trace member 50 other embodiments are contemplated for example as shown in fig1 the trace member 50 may be attached directly to the attachment member 24 to be capable of swaying and the a cam body 68 having a cam part 54 and a protruding part not illustrated formed may be provided on the receiving body 60 also although it is not illustrated the cam body 68 may be provided on the attachment part 24 and the trace member 50 may be provided on the receiving body 60 here in the case when the trace member 50 is not received inside the housing 12 see fig8 a and it in a state being exposed to the outside.