A marking device includes a light-emitting unit configured to emit light, a housing configured to accommodate the light-emitting unit, and a support configured to support the housing. The housing can include a transmitting portion configured to transmit the light from the light-emitting unit through a circumferential portion of the housing, and a roof covering the light-emitting unit accommodated in the housing. The housing can include a side wall formed between every two adjacent windows of the plurality of windows.