To reduce the height (H) of a multi-chip sensor from an ECU substrate mounting surface, as to a multi-chip sensor in which at least an element chip and a signal processing IC chip are housed in a package having the mounting surface used for directly mounting it on an ECU substrate and a flat surface of the element chip is vertical to the mounting surface.

This multi-chip sensor is equipped with the element chip 30 equipped with a sensor detection element, the signal processing IC chip 40 equipped with a signal processing IC for processing an output signal of the detection element, and the package 50 for housing at least the element chip 30 and the IC chip 40 while having the ECU substrate mounting surface. The flat surface of the element chip 30 and the mounting surface are vertical to each other while a flat surface of the IC chip 40 larger than the element chip 30 and the mounting surface are made parallel to each other.