To provide a magnetic sensor capable of supporting a magnetic block stably and allowing a further size reduction of the sensor chip. A magnetic sensor includes a sensor chip and a magnetic block which are mounted on a circuit board. The sensor chip is mounted on the circuit board such that a mounted surface thereof faces a mounting surface, and the magnetic block is mounted on the circuit board such that first and second surfaces and face an element formation surface and the mounting surface, respectively. The magnetic block has a cutout portion, and some of terminal electrodes E11 to E16 are disposed within a space formed by the cutout portion. According to the present invention, the magnetic block can be supported stably. In addition, the presence of the cutout portion in the magnetic block allows a further size reduction of the sensor chip.