Semiconductor failure analysis device and semiconductor failure analysis method

This semiconductor failure analysis device (1) is provided with: a first analysis unit (10) that irradiates first irradiation light (L1) along a first path (R1) set on a first main surface (D1) of a semiconductor device (D); a second analysis unit (20) that irradiates a second irradiation light (L2) along a second path (R2) that is set on a second main surface (D2) that is on the back side of the first main surface (D1); an electric signal acquisition unit (61) that receives an electric signal output by the semiconductor device (D) irradiated by the first irradiation light (L1) and the second irradiation light (L2); and a computer (40) that controls the second analysis unit (20). The size of a first irradiation region (A1) formed on the first main surface (D1) by the first irradiation light (L1) is different from the size of a second irradiation region (A2) formed on the second main surface (D2) by the second irradiation light (L2). The computer (40) irradiates the first irradiation light (L1) and the second