PURPOSE: To make cleaning, disassembing and assembling of an intake box easily, by forming the intake box to be secured to a caburator by coupling the rims of two half bodies of the intage box, together, providing an intake port on one of the half bodies and a net for preventing sucked-in foreign matters in the intake port in an integrated form.

CONSTITUTION: An intake box is constructured by two half bodies 42, 44 made of synthetic resin. One half body 42 is provided with an intake port 46 projecting along the side surface of a caburator 32 and an opening opposed to the intake passage of a caburator 32, and a net 48 for preventing sucked-in foreign matters is provided integrally in the intake port 46. Further, the other half body 44 formed in approximately a cup-shape and is provided with a pluraity of supports 50. Both of the half bodies 42 and 44 are interconnected with each other by screwing clamp rings 58 into the supports 50. Thereby, invasion of the foreign matters such as dust, a bolt/nut or the like, into the intake box 40 and the caburator 32 can be avoided by the net 48. Accordingly, cleaning, disassembling and assembling of the intake box 40 can be easily carried out.