A door opening-closing device , comprising: a drive body having an output shaft that outputs a rotational force transmitted from a drive source ; a rotating body having a rotary shaft for receiving the rotational force of the output shaft to move a door to open and close; a coupling member coupled to an unlocking portion for unlocking the door; and a transmission mechanism being capable of transmit output of the output shaft to the coupling member and the rotating body , wherein the transmission mechanism includes: two screw members, which are male and female screws, one of the two screw members being rotatable about the output shaft and coupled to the output shaft such that it is movable in an axial direction along the output shaft , the other of the two screw members being coupled to the rotary shaft such that it is rotatable about the rotary shaft ; and a transmission member transmitting, to the coupling member , a forward movement force of the one of the two screw members that is moved by receiving the rotational force of the output shaft while meshing with the other of the screw members, to operate the unlocking portion when the door is in a fully close position, wherein the transmission mechanism transmits the rotation of the output shaft to the rotary shaft via the one and the other of the two screw members to open the door after the door is unlocked by the unlocking portion . a drive body having an output shaft that outputs a rotational force transmitted from a drive source ; a rotating body having a rotary shaft for receiving the rotational force of the output shaft to move a door to open and close; a coupling member coupled to an unlocking portion for unlocking the door; and a transmission mechanism being capable of transmit output of the output shaft to the coupling member and the rotating body , wherein the transmission mechanism includes: two screw members, which are male and female screws, one of the two screw members being rotatable about the output shaft and coupled to the output shaft such that it is movable in an axial direction along the output shaft , the other of the two screw members being coupled to the rotary shaft such that it is rotatable about the rotary shaft ; and a transmission member transmitting, to the coupling member , a forward movement force of the one of the two screw members that is moved by receiving the rotational force of the output shaft while meshing with the other of the screw members, to operate the unlocking portion when the door is in a fully close position, two screw members, which are male and female screws, one of the two screw members being rotatable about the output shaft and coupled to the output shaft such that it is movable in an axial direction along the output shaft , the other of the two screw members being coupled to the rotary shaft such that it is rotatable about the rotary shaft ; and a transmission member transmitting, to the coupling member , a forward movement force of the one of the two screw members that is moved by receiving the rotational force of the output shaft while meshing with the other of the screw members, to operate the unlocking portion when the door is in a fully close position, wherein the transmission mechanism transmits the rotation of the output shaft to the rotary shaft via the one and the other of the two screw members to open the door after the door is unlocked by the unlocking portion . <EOS>