[Problem] To provide a method of manufacture for an encased coil body, which is capable of easily manufacturing an encased coil body which is configured so as to be encased in a state where a coil is enclosed within an electrically insulating resin and is also capable of favorably preventing the coil from positional misalignment or deformation at the time of the manufacture,[Means for Solution] The method includes injection-molding a resin covering layer which encases the coil 10 with a thermoplastic resin, in which the injection-molding is carried out such that the injection-molding step is divided into a primary molding step and a secondary molding step, in which the primary molding step includes contacting a primary molding die to an inner circumferential surface of the coil 10 and molding a primary molded body 22-1 which includes an outer circumferential covering portion 46 in a state where the coil 10 is constrained so as to be positioned in a radial direction, and the secondary molding step includes, after the primary molding step, setting the primary molded body 22-1 along with the coil 10 to a secondary molding die and molding a secondary molded body which includes an inner circumferential covering portion.