An air-sending device comprising: - a housing including an inlet air passage and an outlet air passage , the inlet air passage communicating with an air inlet disposed at one side of the housing, the outlet air passage communicating with an air outlet ; - a first partition plate partitioning an interior of the housing into the inlet air passage and the outlet air passage ; - a bell mouth disposed around an opening defined in the first partition plate ; and - an impeller disposed over the first partition plate with the bell mouth interposed between the impeller and the first partition plate , the impeller having a rotation axis that extends in a direction that intersects the first partition plate , - the impeller being configured to suction air into the inlet air passage from the air inlet , blow out air in a circumferential direction of the impeller , and blow out air from the air outlet through the outlet air passage , - the inlet air passage having a width (W) greater than an outside diameter of the impeller , the inlet air passage guiding air from the air inlet along the first partition plate to the opening of the first partition plate , and having an air-passage wall (9-1 to 9-6, 12), the air-passage wall being located at a position in the inlet air passage that is past a center of the opening along the first partition plate from the air inlet , characterised by - the air-passage wall (9-1 to 9-6, 12) being equal in width to the inlet air passage and the air-passage wall being equal in dimension along the rotation axis to the inlet air passage, and - at an inlet of the bell mouth , a distance (L) from the rotation axis of the impeller to the air-passage wall being less than a distance (X) from the rotation axis of the impeller to an end portion of the bell mouth that is close to the air inlet ; such that air is prevented from entering the impeller from an area located farther from the air inlet than is the air-passage wall (9-1 to 9-6, 12). - a housing including an inlet air passage and an outlet air passage , the inlet air passage communicating with an air inlet disposed at one side of the housing, the outlet air passage communicating with an air outlet ; - a first partition plate partitioning an interior of the housing into the inlet air passage and the outlet air passage ; - a bell mouth disposed around an opening defined in the first partition plate ; and - an impeller disposed over the first partition plate with the bell mouth interposed between the impeller and the first partition plate , the impeller having a rotation axis that extends in a direction that intersects the first partition plate , - the impeller being configured to suction air into the inlet air passage from the air inlet , blow out air in a circumferential direction of the impeller , and blow out air from the air outlet through the outlet air passage , - the inlet air passage having a width (W) greater than an outside diameter of the impeller , the inlet air passage guiding air from the air inlet along the first partition plate to the opening of the first partition plate , and having an air-passage wall (9-1 to 9-6, 12), the air-passage wall being located at a position in the inlet air passage that is past a center of the opening along the first partition plate from the air inlet , characterised by - the air-passage wall (9-1 to 9-6, 12) being equal in width to the inlet air passage and the air-passage wall being equal in dimension along the rotation axis to the inlet air passage, and - at an inlet of the bell mouth , a distance (L) from the rotation axis of the impeller to the air-passage wall being less than a distance (X) from the rotation axis of the impeller to an end portion of the bell mouth that is close to the air inlet ; <EOS>