To heighten the versatility by simply and accurately controlling the total width in a door opening and closing device.

A first board 17 is loaded with a motor 15 and a first driven pulley 13, and a second board 18 is loaded with a second driven pulley 14. The lengths of a second normal tension wire 21 laid on the second driven pulley 14 and a driving pulley 16 and a second reverse tension wire 22 are previously set to a length corresponding to the maximum total width dimensions of a pair of right and left doors 4, 5 as fitting objects. Thus, according to the size of the total width of the paired right and left doors 4, 5 of a Buddhist family altar 1 as a required object of a door opening and closing device 10, the isolated space between the first driven pulley 13 and the second driven pulley 14 can be arbitrarily controlled without replacement of components to the narrowed state as shown in Fig. 2 or to the widened state as shown in Fig. 8.