PURPOSE: To easily and properly hold flowers, in a flower arranging auxiliary device consisting of an elastic deformable base material to be fitted in the opening of a vase, by inserting the stalk or the like of flowers in the auxiliary device.

CONSTITUTION: An auxiliary device A that is removably fitted in the inside of the opening K' of a flower vase K and also that consists of an elastic deformable base material provided with retaining holes 10a, 10b, etc., for insertedly retaining flowers F arranged in the vase K is provided with a retaining part provided with the retaining holes 10a, 10b, etc., and elastic supporting means 11 which are elastically brought into contact with the inside surface K" of the opening K' of the vase K for supporting the auxiliary device A against the surface K", and also the retaining part of the auxiliary devices A, A' is provided with a ring-shaped retainer 20.