A power train support structure for a vehicle, the structure being configured to support a power train disposed to be offset to one of left and right sides within an accommodation room formed in a vehicle front portion, comprising: a first front side frame disposed on one of left and right sides of the power train; a second front side frame disposed on the other of the left and right sides of the power train, the second front side frame being greatly away from the power train with respect to the first front side frame; a mounting bracket extending in a left-right direction between the second front side frame and the power train, one of left and right ends of the mounting bracket being connected to the power train; and a connecting member for connecting the other of the left and right ends of the mounting bracket and the second front side frame, wherein the mounting bracket includes a front fixing portion to be fixed to the power train, and a rear fixing portion (32c, 32d) to be fixed to the power train on a rear side with respect to the front fixing portion, when a collision load from a front side acts on the power train, a strength of each of the front fixing portion and the rear fixing portion (32c, 32d) is set to such a strength that the rear fixing portion (32c, 32d) is broken by the collision load and the front fixing portion is not broken in such a way that the power train in a plan view retracts, while performing yaw motion substantially around a predetermined portion (α1) of the connecting member, the collision load from the front side is a collision load acting on the power train obliquely from a front side and one of left and right sides, the vehicle further includes a floor panel for defining a bottom surface of a passenger compartment, a dashboard panel for separating the accommodation room and the passenger compartment, and a tunnel portion formed on the floor panel and bulging upwardly, an opening portion opened in an intermediate portion of a lower end of the dashboard panel in the left-right direction is formed in a front end of the tunnel portion, the mounting bracket further includes a lower fixing portion to be fixed to the power train on a lower side with respect to the front fixing portion, and a reinforcement rib for reinforcing the front fixing portion in such a way that a strength of the front fixing portion increases, as compared with the other fixing portions, and when the collision load obliquely from the front side acts on the power train, a strength of the lower fixing portion is set to such a strength that the lower fixing portion is broken by the collision load in such a way that the power train retracts toward the opening portion of the tunnel portion. a first front side frame disposed on one of left and right sides of the power train; a second front side frame disposed on the other of the left and right sides of the power train, the second front side frame being greatly away from the power train with respect to the first front side frame; a mounting bracket extending in a left-right direction between the second front side frame and the power train, one of left and right ends of the mounting bracket being connected to the power train; and a connecting member for connecting the other of the left and right ends of the mounting bracket and the second front side frame, wherein the mounting bracket includes a front fixing portion to be fixed to the power train, and a rear fixing portion (32c, 32d) to be fixed to the power train on a rear side with respect to the front fixing portion, when a collision load from a front side acts on the power train, a strength of each of the front fixing portion and the rear fixing portion (32c, 32d) is set to such a strength that the rear fixing portion (32c, 32d) is broken by the collision load and the front fixing portion is not broken in such a way that the power train in a plan view retracts, while performing yaw motion substantially around a predetermined portion (α1) of the connecting member, the collision load from the front side is a collision load acting on the power train obliquely from a front side and one of left and right sides, the vehicle further includes a floor panel for defining a bottom surface of a passenger compartment, a dashboard panel for separating the accommodation room and the passenger compartment, and a tunnel portion formed on the floor panel and bulging upwardly, an opening portion opened in an intermediate portion of a lower end of the dashboard panel in the left-right direction is formed in a front end of the tunnel portion, the mounting bracket further includes a lower fixing portion to be fixed to the power train on a lower side with respect to the front fixing portion, and a reinforcement rib for reinforcing the front fixing portion in such a way that a strength of the front fixing portion increases, as compared with the other fixing portions, and when the collision load obliquely from the front side acts on the power train, a strength of the lower fixing portion is set to such a strength that the lower fixing portion is broken by the collision load in such a way that the power train retracts toward the opening portion of the tunnel portion.