Coincidence measurement of energy-selected electrons and mass-selected ions (electron-ion coincidence (EICO) spectroscopy) is a powerful technique to clarify the ion desorption mechanism induced by electron transitions, because excited states leading to ion desorption are directly identified. Information on the coincidence ions, however, has been limited so far to the mass and the yield. In order to obtain information on the kinetic energy and the desorption polar angle of ions, we have developed a new electron-polar-angle-resolved-ion coincidence apparatus, which consists of a coaxially symmetric mirror electron energy analyzer and a miniature polar-angle-resolved time-of-flight ion mass spectrometer ((TOF-MS)). The TOF-MS consists of a shield for the electric field, an ion drift electrode with three meshes, and microchannel plates with three concentric anodes. By using SIMION 3D version 7.0 we simulated ion trajectories of H + for the TOF-MS with a drift bias of -30 V. The results show that the desorption angles of H + with a kinetic energy of 3 eV detected by the innermost anode, the intermediate anode, and the outermost anode are 0 • -17 • , 22 • -48 • , and 57 • -90 • , respectively. By assembling a miniature cylindrical mirror electron energy analyzer (CMA) with a diameter of 26 mm in a coaxially symmetric mirror analyzer coaxially and confocally we have developed an apparatus for Auger-photoelectron coincidence spectroscopy (APECS). The CMA consists of a shield for the electric field, inner and outer cylinders, a pinhole, and an electron multiplier. The performance was tested by measuring Si LVV Auger-Si 2p photoelectron coincidence spectra of a Si(111) surface. Features of the APECS apparatus are as follows: 1) Coincidence signal detection efficiency is improved by one order of magnitude from previous ones because of the large solid angle of the coaxially symmetric mirror analyzer and the CMA. 2) Positioning is quite easy, because the coaxially symmetric mirror analyzer and the CMA are assembled confocally on a rod with a mechanism for xyz positioning and tilt adjustment. 3) It can be installed in a multi-purpose ultrahigh vacuum chamber because it is constructed on a 203 mm-outer-diameter conflat flange with a 50 mm retractable mechanism. 4) The production cost is low because the structure is simple and the number of parts is relatively small.