A stator assembly method in which coils that have slot housed portions (30, 32) and coil end portions (34, 36) formed from a conductive wire are mounted to an annular stator core that has a plurality of teeth that extend from a back yoke toward an inner side in a radial direction and slots formed between two of the teeth, comprising: a coil assembly forming step of forming a coil assembly in which a plurality of the coils are disposed in an annular arrangement and in which the slot housed portions (30, 32) of two of the coils to be housed in the same slot of the stator core form slot housed bundles; a jig disposing step of moving guide jigs including first guide jigs configured to form guide surfaces with respect to holes, of the coil assembly, formed between two of the slot housed bundles disposed adjacent to each other in the circumferential direction and inserting the guide jigs into the holes to dispose the guide jigs with respect to the coil assembly; and a coil inserting step of pushing out the plurality of the coils which constitute the coil assembly radially from a radially inner side toward a radially outer side, with the coil assembly disposed in a radially inner space of the stator core and with the first guide jigs being provided adjacently on the radially inner side of the teeth to oppose the teeth and with the slot housed portions (30, 32) of the coils provided adjacently on the radially inner side of the slots to oppose the slots and with the guide surfaces of the first guide jigs being in parallel with side surfaces of the teeth that face the slots in the circumferential direction, to insert the slot housed portions (30, 32) of the coils into the slots of the stator core while the guide jigs are guiding the plurality of the coils, wherein the first guide jigs are formed such that a width at the position of the radially outer end is the same as or slightly larger than the width at the distal end of the teeth of the stator core; a width of the first guide jigs gradually becomes smaller from the radially outer side toward the radially inner side; and the jig disposing step includes disposing the guide jigs with respect to the coil assembly such that the one side of the first guide jigs faces the radially outer side of the coil assembly and the other side of the first guide jigs faces the radially inner side of the coil assembly. a coil assembly forming step of forming a coil assembly in which a plurality of the coils are disposed in an annular arrangement and in which the slot housed portions (30, 32) of two of the coils to be housed in the same slot of the stator core form slot housed bundles; a jig disposing step of moving guide jigs including first guide jigs configured to form guide surfaces with respect to holes, of the coil assembly, formed between two of the slot housed bundles disposed adjacent to each other in the circumferential direction and inserting the guide jigs into the holes to dispose the guide jigs with respect to the coil assembly; and a coil inserting step of pushing out the plurality of the coils which constitute the coil assembly radially from a radially inner side toward a radially outer side, with the coil assembly disposed in a radially inner space of the stator core and with the first guide jigs being provided adjacently on the radially inner side of the teeth to oppose the teeth and with the slot housed portions (30, 32) of the coils provided adjacently on the radially inner side of the slots to oppose the slots and with the guide surfaces of the first guide jigs being in parallel with side surfaces of the teeth that face the slots in the circumferential direction, to insert the slot housed portions (30, 32) of the coils into the slots of the stator core while the guide jigs are guiding the plurality of the coils, wherein the first guide jigs are formed such that a width at the position of the radially outer end is the same as or slightly larger than the width at the distal end of the teeth of the stator core; a width of the first guide jigs gradually becomes smaller from the radially outer side toward the radially inner side; and the jig disposing step includes disposing the guide jigs with respect to the coil assembly such that the one side of the first guide jigs faces the radially outer side of the coil assembly and the other side of the first guide jigs faces the radially inner side of the coil assembly.