A semiconductor device can include an active region having a fin portion providing a channel region between opposing source and drain regions. Essentially, instead of using the seldom-used poll requests one per service flow, this same request opportunity is pointed to multiple service flows. By fixing the sunshade cloth on the the supporting part with a fastener, the sunshade cloth can slide relative to the supporting part, thereby the sunshade cloth can be fixed securely at place on the supporting apart and can shelter sunlight illuminating from various angles. Based on a signal from the negative pressure sensor 10, a compressed air generation source 20 supplies a compressed air to the vacuum pipe 9 and thereby stabilizes the vacuum level in the vacuum pipe 9.