A battery mounting structure for an electric automobile, the battery mounting structure comprising: a battery case (20; 80) containing a battery cell; a battery case holder arranged in a vehicle body of the electric automobile, wherein the battery case holder is capable of accommodating the battery case (20; 80); a battery fastening mechanism (29 to 31, 51 to 53) that fastens the battery case (20; 80), which is accommodated in the battery case holder, to the vehicle body; and a battery case guiding mechanism (32 to 35, 55 to 58) that guides the battery case (20; 80) to the battery case holder when the battery case (20; 80) is raised from below the vehicle body and accommodated in the battery case holder, wherein the battery case (20; 80) includes four side surfaces (21, 22, 23, 24; 81, 82, 89, 84) facing front, rear, left, and right directions and forming outer sides of the battery case (20; 80), a first corner (25; 91) formed by two first side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, and a second corner (28; 88) formed by two remaining second side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, characterized in that the battery case guiding mechanism (32 to 35, 55 to 58) includes a case side member (32; 101, 33, 34, 35) arranged at a portion of each of the first side surfaces near the first corner (25; 91) and at a portion of each of the second side surfaces near the second corner (28; 88), and a vehicle body side member (55, 56, 57, 58) arranged on the vehicle body, wherein the vehicle body side member (55, 56, 57, 58) can contact the case side member (32; 101, 33, 34, 35), and wherein one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes a convex-curved surface (39B; 102B), and the other one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes an inclined surface that can contact the convex-curved surface. a battery case (20; 80) containing a battery cell; a battery case holder arranged in a vehicle body of the electric automobile, wherein the battery case holder is capable of accommodating the battery case (20; 80); a battery fastening mechanism (29 to 31, 51 to 53) that fastens the battery case (20; 80), which is accommodated in the battery case holder, to the vehicle body; and a battery case guiding mechanism (32 to 35, 55 to 58) that guides the battery case (20; 80) to the battery case holder when the battery case (20; 80) is raised from below the vehicle body and accommodated in the battery case holder, wherein the battery case (20; 80) includes four side surfaces (21, 22, 23, 24; 81, 82, 89, 84) facing front, rear, left, and right directions and forming outer sides of the battery case (20; 80), a first corner (25; 91) formed by two first side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, and a second corner (28; 88) formed by two remaining second side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, characterized in that the battery case guiding mechanism (32 to 35, 55 to 58) includes a case side member (32; 101, 33, 34, 35) arranged at a portion of each of the first side surfaces near the first corner (25; 91) and at a portion of each of the second side surfaces near the second corner (28; 88), and a vehicle body side member (55, 56, 57, 58) arranged on the vehicle body, wherein the vehicle body side member (55, 56, 57, 58) can contact the case side member (32; 101, 33, 34, 35), and wherein one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes a convex-curved surface (39B; 102B), and the other one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes an inclined surface that can contact the convex-curved surface. wherein the battery case (20; 80) includes four side surfaces (21, 22, 23, 24; 81, 82, 89, 84) facing front, rear, left, and right directions and forming outer sides of the battery case (20; 80), a first corner (25; 91) formed by two first side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, and a second corner (28; 88) formed by two remaining second side surfaces, among the four side surfaces (21, 22, 23, 24; 81, 82, 89, 84), intersecting each other at a right angle, characterized in that the battery case guiding mechanism (32 to 35, 55 to 58) includes a case side member (32; 101, 33, 34, 35) arranged at a portion of each of the first side surfaces near the first corner (25; 91) and at a portion of each of the second side surfaces near the second corner (28; 88), and a vehicle body side member (55, 56, 57, 58) arranged on the vehicle body, wherein the vehicle body side member (55, 56, 57, 58) can contact the case side member (32; 101, 33, 34, 35), and wherein one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes a convex-curved surface (39B; 102B), and the other one of the case side member (32; 101, 33, 34, 35) and the vehicle side member (55, 56, 57, 58) includes an inclined surface that can contact the convex-curved surface.