A vibration detection device for detecting vibration of a cartridge including a bearing housing that accommodates a rotor coupling a wheel and a rotor shaft, and a bearing rotatably supporting the rotor, the bearing housing including a lubricant-oil passage port for allowing lubricant oil to pass through an interior of the bearing housing, the vibration detection device comprising: a sensor mount attached to an oil-flow-passage forming member configured to be capable of connecting to and separating from the bearing housing, the oil-flow-passage forming member including, inside thereof, an oil flow passage through which one of lubricant oil to be supplied to the interior of the bearing housing via the lubricant-oil passage port or lubricant oil discharged from the interior of the bearing housing via the lubricant-oil passage port flows; a vibration sensor disposed on the sensor mount; and characterized in that a vibration transmission leg portion is connected to the sensor mount and configured to be in contact with the bearing housing in a state where the oil-flow-passage forming member is connected to the bearing housing, wherein the oil-flow-passage forming member includes: a rigid portion to which the sensor mount is attached; and a soft portion connected to the rigid portion, configured to be capable of connecting to and separating from the bearing housing, and formed of a softer material than the rigid portion, wherein the soft portion includes, on a surface being in contact with the bearing housing in a state where the oil-flow-passage forming member is connected to the bearing housing, an end portion of the oil flow passage facing the lubricant-oil passage port, formed on the soft portion, and wherein the oil-flow-passage forming member includes a through hole formed through at least an interior of the soft portion, the through hole being inserted onto the vibration transmission leg portion. a sensor mount attached to an oil-flow-passage forming member configured to be capable of connecting to and separating from the bearing housing, the oil-flow-passage forming member including, inside thereof, an oil flow passage through which one of lubricant oil to be supplied to the interior of the bearing housing via the lubricant-oil passage port or lubricant oil discharged from the interior of the bearing housing via the lubricant-oil passage port flows; a vibration sensor disposed on the sensor mount; and characterized in that a vibration transmission leg portion is connected to the sensor mount and configured to be in contact with the bearing housing in a state where the oil-flow-passage forming member is connected to the bearing housing, wherein the oil-flow-passage forming member includes: a rigid portion to which the sensor mount is attached; and a soft portion connected to the rigid portion, configured to be capable of connecting to and separating from the bearing housing, and formed of a softer material than the rigid portion, a rigid portion to which the sensor mount is attached; and a soft portion connected to the rigid portion, configured to be capable of connecting to and separating from the bearing housing, and formed of a softer material than the rigid portion, wherein the soft portion includes, on a surface being in contact with the bearing housing in a state where the oil-flow-passage forming member is connected to the bearing housing, an end portion of the oil flow passage facing the lubricant-oil passage port, formed on the soft portion, and wherein the oil-flow-passage forming member includes a through hole formed through at least an interior of the soft portion, the through hole being inserted onto the vibration transmission leg portion.