CALorimetric Electron Telescope (CALET) is planned to be placed on the International Space Station in 2014 to carry out the accurate measurements of electrons in 1 GeV - 20 TeV, gamma-rays in 10 GeV - 10 TeV, and protons and nuclei in several 10 GeV - 1000 TeV. The main calorimeter consists of a Charge Detector (CHD), an Imaging Calorimeter (IMC), and a Total Absorption Calorimeter (TASC). The total thickness is 30 X0 for electromagnetic particles or 1.3 λ for protons. CALET, with its imaging and deep calorimeter, provides excellent energy resolution and high background rejection. We carried out beam tests to assess the detector performances and the validity of our Monte Carlo simulations, using 10 - 290 GeV electron and 30 - 400 GeV proton beams at CERN-SPS. In this paper, we present the expected performance based on the agreement between measurements and predictions from the Monte Carlo simulations, including angular and energy resolutions and particle identification.