A simple model for calculating the particle-vibration form factor is studied. Explicit expressions of the latter quantity are worked out for various kinds of vibrations, assuming a static, zero range effective interaction. Numerical results for (T=0) and (T = 1) octupole vibrations, for Fermi and Gamow-Teller vibrations are given. The influence of the range of the effective interaction is discussed in relation with the nature of the vibration.