To solve the problems that in a conventional grain container, an underframe base can not be removed since it is fixed to a deck, although a pole, a beam and a hopper can be removed, and when it is used as an ordinary truck, the storing space of the deck becomes small or the like.

In the container to store and convey a grain, the underframe base 2 framed in a rectangular parallelepiped is fixed to the deck 1 of a truck and the poles 3 are fitted on the four corners of the underframe base 2 attachably and detachably and also the beam 4 furnished with the hopper 5 is fitted on the poles 3 attachably and detachably, wherein the underframe base 2 is composed of a plurality of decomposable members and is fitted on the deck 1 attachably and detachably.