A permanent magnet embedded electric motor, comprising: a stator; and a rotor (5; 105) arranged rotatably so as to face the stator, wherein the rotor (5; 105) has a plurality of magnet insertion holes formed in a rotor core thereof, wherein flux barriers are formed on both sides of the magnet insertion hole in a circumferential direction, wherein a corresponding permanent magnet is inserted in each of the plurality of magnet insertion holes, wherein a plurality of slits are formed between each of the magnet insertion holes in the rotor core and a core outer peripheral surface of the rotor core, wherein the plurality of slits are arranged in a circumferential direction of the rotor core, wherein each of the plurality of slits extends further in a magnet thickness direction than in a magnet width direction, characterized in that an interval between the flux barriers on both sides of each magnet insertion hole is smaller than a width (Wd) of the permanent magnet, a hole defining portion of each of the magnet insertion holes includes a pair of extended portions (11b; 111b) of the rotor core, the extended portion (11b; 111b) projects toward an interpolar core portion in the rotor core in an area positioned further on an outer side of a circumferential direction with respect to a width-direction end surface of the corresponding permanent magnet, an interval (Wc) in the magnet width direction between tip ends of the pair of the extended portions is larger than the width (Wd) of the permanent magnet, the slits are arranged within the interval S between the corresponding pair of the flux barriers, and Lb is larger than La, and Lc is smaller than Ld, where La represents a distance between the plurality of slits and the core outer peripheral surface; Lb represents a distance between the plurality of slits and an outer peripheral-side surface of the permanent magnet; Lc represents a shortest distance between the extended portion (11b; 111b) and the interpolar core portion; and Ld represents a thickness of the permanent magnet. a stator; and a rotor (5; 105) arranged rotatably so as to face the stator, wherein the rotor (5; 105) has a plurality of magnet insertion holes formed in a rotor core thereof, wherein flux barriers are formed on both sides of the magnet insertion hole in a circumferential direction, wherein a corresponding permanent magnet is inserted in each of the plurality of magnet insertion holes, wherein a plurality of slits are formed between each of the magnet insertion holes in the rotor core and a core outer peripheral surface of the rotor core, wherein the plurality of slits are arranged in a circumferential direction of the rotor core, wherein each of the plurality of slits extends further in a magnet thickness direction than in a magnet width direction, characterized in that an interval between the flux barriers on both sides of each magnet insertion hole is smaller than a width (Wd) of the permanent magnet, a hole defining portion of each of the magnet insertion holes includes a pair of extended portions (11b; 111b) of the rotor core, the extended portion (11b; 111b) projects toward an interpolar core portion in the rotor core in an area positioned further on an outer side of a circumferential direction with respect to a width-direction end surface of the corresponding permanent magnet, an interval (Wc) in the magnet width direction between tip ends of the pair of the extended portions is larger than the width (Wd) of the permanent magnet, the slits are arranged within the interval S between the corresponding pair of the flux barriers, and Lb is larger than La, and Lc is smaller than Ld, where La represents a distance between the plurality of slits and the core outer peripheral surface; Lb represents a distance between the plurality of slits and an outer peripheral-side surface of the permanent magnet; Lc represents a shortest distance between the extended portion (11b; 111b) and the interpolar core portion; and Ld represents a thickness of the permanent magnet.