The motor-operated valve of the present invention reduces magnetic flux leakage between the yoke (413A) and the magnetic pole plate (42A) of coil parts (41A, 41B) and facilitates assembly of the coilparts. A magnetic rotor (43) and a pole plate (42A) of a stepping motor (40) are disposed inside a closed box (8). The coil parts (41A, 41B) are disposed outside the closed box (8). An expansion portion (413A1) of the yoke (413A) contacts the top plate (81) of the closed box (8); a common base (42A1) of the pole plate (42A) is in surface contact with the inner surface of the top plate (81). Expansion portions (413B1, 413C1) of the yokes (413B, 413C) are in surface contact with the outer peripheral surface of the side surface portion (82) of the closed box (8); the common base (42BC1) of the magnetic pole plate (42BC) is in surface contact with the inner peripheral surface of the side surface portion (82).