In the canned linear motor armature, both the side surfaces of the armature winding (18) are fixed by two winding fixing frames (4) so as to sandwich the armature winding in between them in the longitudinal direction. A refrigerant passage (5) is provided in a space between the can (3) and the winding fixing frame (4). A seal material (24) is provided in a gap between a case (2) and the winding fixing frame (4) to prevent a refrigerant supplied to the refrigerant passage (5) from leaking to the armature winding (18) sandwiched in between the two winding fixing frames (4) to impregnate the armature winding (18) with the refrigerant. A waterproof film is adhered onto a surface of the winding fixing frame (4) where the refrigerant comes into contact.