A theoretical model of flare which explains observed quantities in Hα, EUV, soft X-ray and flare-associated solar wind is presented. It is assumed that large mass observed in the soft X-ray flare and the solar wind comes from the chromosphere by the process like evaporation while flare is in progress. From mass and pressure balance in the chromosphere and the corona, the high temperature in the soft X-ray flare is shown to be attained by the larger mass loss to the solar wind compared with the mass remained in the corona, in accord with observations. The total energy of 1032 erg, the electron density of 1013.5 cm−3 in Hα flare, the temperature of the X-ray flare of 107.3K and the time to attain maximum Hα brightness (600 s) are derived consistent with observations. It is shown that the top height of the Hα flare is located about 1000 km lower than that of the active chromosphere because of evaporation. So-called limb flares are assigned to either post-flare loops, surges or rising prominences.