An inclination sensor device comprising: a substrate which mounts an inclination sensor configured to calculate an inclination angle of a vehicle; a case which accommodates the substrate; a first positioning mechanism which positions the substrate relative to the case in a first direction that is substantially parallel to a first main surface of the substrate; and a second positioning mechanism which positions the substrate relative to the case in a second direction that is substantially perpendicular to the first main surface of the substrate, wherein at least one of the first positioning mechanism and the second positioning mechanism comprises: a protrusion (158, 164) provided on one of the substrate and the case; and a protrusion receiving portion (128, 132) provided in the other of the substrate and the case, wherein the substrate is positioned relative to the case by press-fitting the protrusion to the protrusion receiving portion, and wherein the case comprises: a main body portion having a first inner wall and an opening opposite to the first inner wall; and a cover portion which covers the opening to face the first inner wall, wherein the substrate comprises: the first main surface of the substrate on which the inclination sensor is mounted; a second main surface opposite to the first main surface; and a first side surface between the first main surface and the second main surface and facing the first inner wall, characterized in that the protrusion is provided on one of the first inner wall and the first side surface, and the protrusion receiving portion is provided in the other of the first inner wall and the first side surface, and wherein an insertion direction of the substrate to the main body portion is the same as a press-fitting direction of the protrusion (158, 164) to the protrusion receiving portion (128, 132), and while the substrate is inserted into the main body portion, the protrusion is press-fitted to the protrusion receiving portion, wherein the substrate further comprises: a second side surface opposite to the first side surface and facing the cover portion, and wherein in addition to the protrusion, another protrusion is provided on one of the cover portion and the second side surface, and in addition to the protrusion receiving portion, another protrusion receiving portion is provided in the other of the cover portion and the second side surface. a substrate which mounts an inclination sensor configured to calculate an inclination angle of a vehicle; a case which accommodates the substrate; a first positioning mechanism which positions the substrate relative to the case in a first direction that is substantially parallel to a first main surface of the substrate; and a second positioning mechanism which positions the substrate relative to the case in a second direction that is substantially perpendicular to the first main surface of the substrate, wherein at least one of the first positioning mechanism and the second positioning mechanism comprises: a protrusion (158, 164) provided on one of the substrate and the case; and a protrusion receiving portion (128, 132) provided in the other of the substrate and the case, a protrusion (158, 164) provided on one of the substrate and the case; and a protrusion receiving portion (128, 132) provided in the other of the substrate and the case, wherein the substrate is positioned relative to the case by press-fitting the protrusion to the protrusion receiving portion, and wherein the case comprises: a main body portion having a first inner wall and an opening opposite to the first inner wall; and a cover portion which covers the opening to face the first inner wall, a main body portion having a first inner wall and an opening opposite to the first inner wall; and a cover portion which covers the opening to face the first inner wall, wherein the substrate comprises: the first main surface of the substrate on which the inclination sensor is mounted; a second main surface opposite to the first main surface; and a first side surface between the first main surface and the second main surface and facing the first inner wall, characterized in that the protrusion is provided on one of the first inner wall and the first side surface, and the protrusion receiving portion is provided in the other of the first inner wall and the first side surface, and the first main surface of the substrate on which the inclination sensor is mounted; a second main surface opposite to the first main surface; and a first side surface between the first main surface and the second main surface and facing the first inner wall, characterized in that the protrusion is provided on one of the first inner wall and the first side surface, and the protrusion receiving portion is provided in the other of the first inner wall and the first side surface, and wherein an insertion direction of the substrate to the main body portion is the same as a press-fitting direction of the protrusion (158, 164) to the protrusion receiving portion (128, 132), and while the substrate is inserted into the main body portion, the protrusion is press-fitted to the protrusion receiving portion, wherein the substrate further comprises: a second side surface opposite to the first side surface and facing the cover portion, and wherein a second side surface opposite to the first side surface and facing the cover portion, and wherein in addition to the protrusion, another protrusion is provided on one of the cover portion and the second side surface, and in addition to the protrusion receiving portion, another protrusion receiving portion is provided in the other of the cover portion and the second side surface.