A magnetic detection sensor for being installed at an end of a cable with a pair of signal wires to detect a magnetic field from magnetic poles. The sensor includes a magnetic sensor including a detection section and a pair of lead frames, the detection section including a magnetic detection element for detecting the magnetic field from the magnetic poles, and the lead frames extending from the detection section and configured to output a detection signal of the detection section, a housing portion that houses the magnetic sensor, and a capacitor that is provided separately from the magnetic sensor and is housed in the housing portion. First joining portions respectively joining the pair of lead frames to the pair of signal wires and second joining portions respectively joining the pair of lead frames to a pair of lead wires of the capacitor are located inside the housing portion.