A particle-moving type orientation sensor including a housing, at least one light emitter, two light receivers, and a plurality of particles. The housing has an accommodating space having four zones, which are circularly arranged. A first opening is formed on the housing and connecting to a first zone. Two second openings are formed on the housing and respectively connecting to a second zone and a fourth zone. The light emitter emits light into the accommodating space through the first opening. The light receivers respectively receive light from the accommodating space through the second openings. The particles are arranged in the accommodating space. While the particle-moving type orientation sensor is tilting, the light emitter is partially blocked by the particles, and one of the light receivers is partially blocked by the particles, the light receivers respectively receive light with predetermined intensities and output electric signals with predetermined strengths.