A sensor device comprising: a holder that surrounds a circuit member, to which an electronic component is electrically connected, and a sensor element electrically connected to the circuit member; and a housing formed by injection molding so as to cover the holder, wherein a suppression portion is provided inside the holder, the suppression portion extending in a column shape so as to connect between inner portions of the holder in a direction of deformation of the holder due to a molding pressure during the injection molding in order to suppress the deformation, the holder is constituted from at least a first holder and a second holder, and surrounds the circuit member and the sensor element between the first holder and the second holder; the first holder has a first magnetism collection portion holder comprising a first holder body portion; the second holder has a second magnetism collection portion holder comprising a second holder body portion that includes a placement portion, on which the circuit member and the sensor element are placed, and that faces the first holder body portion, and the suppression portion that projects from the second holder body portion toward the first holder body portion; the second holder body portion has a side wall, the placement portion is formed to be recessed with respect to the side wall, the side wall has long side walls and a short side wall corresponding to a rectangular shape of the second magnetism collection portion holder, the short side wall is provided at the distal end portion of the second holder body portion in a direction in which the second magnetism collection portion holder extends, the long side walls are provided at end portions of the second holder body portion in a direction that is orthogonal to said direction and face each other, the side wall separates an internal space, which is formed between the first magnetism collection portion holder and the second magnetism collection portion holder, and the outside from each other, characterized in that the suppression portion is provided integrally with the second holder body portion, at a portion of the placement portion. a holder that surrounds a circuit member, to which an electronic component is electrically connected, and a sensor element electrically connected to the circuit member; and a housing formed by injection molding so as to cover the holder, wherein a suppression portion is provided inside the holder, the suppression portion extending in a column shape so as to connect between inner portions of the holder in a direction of deformation of the holder due to a molding pressure during the injection molding in order to suppress the deformation, the holder is constituted from at least a first holder and a second holder, and surrounds the circuit member and the sensor element between the first holder and the second holder; the first holder has a first magnetism collection portion holder comprising a first holder body portion; the second holder has a second magnetism collection portion holder comprising a second holder body portion that includes a placement portion, on which the circuit member and the sensor element are placed, and that faces the first holder body portion, and the suppression portion that projects from the second holder body portion toward the first holder body portion; the second holder body portion has a side wall, the placement portion is formed to be recessed with respect to the side wall, the side wall has long side walls and a short side wall corresponding to a rectangular shape of the second magnetism collection portion holder, the short side wall is provided at the distal end portion of the second holder body portion in a direction in which the second magnetism collection portion holder extends, the long side walls are provided at end portions of the second holder body portion in a direction that is orthogonal to said direction and face each other, the side wall separates an internal space, which is formed between the first magnetism collection portion holder and the second magnetism collection portion holder, and the outside from each other, characterized in that the suppression portion is provided integrally with the second holder body portion, at a portion of the placement portion.