標準的な予備的貯蓄モデルに正規，非正規および失職という雇用形態変化リスクを導入し，近年の日本の若年層が直面する雇用・所得リスクの評価を試みた．『21世紀成年者縦断調査』のミクロデータを用い，所得・雇用リスクを雇用形態ごとに比較すると，正規雇用者に比べ，非正規雇用者は高い失職確率，低い賃金水準，高い所得分散というリスクを負っている．そのため，正規から非正規に雇用形態が変化すると消費水準が低下する．一方，非正規から正規に転換すると消費水準が増加する．この実証結果を動学モデルを用いて要因分解を行った結果，正規・非正規間の雇用形態変化に関しては，最も重要な要因は平均賃金の差であり，続いて失職確率の差となり，雇用形態を所与とした所得変動リスクの差は大きな効果をもたらさないという結果を得た．This study investigates the importance of various risks faced by Japanese youth on the basis of a precautionary saving model with different employment status such as regular, irregular, and unemployment. Using large panel data covering about 30,000 individuals from the annual Longitudinal Survey of Adults in 21st Century conducted by the Ministry of Health, Labour and Welfare, we find that irregular workers face (1) higher risks of losing jobs, (2) lower wages, and (3) larger income variations than regular workers. When workers' job status changes from regular to irregular and vice versa, their consumption levels tend to decrease and increase, respectively. A dynamic model of consumption and employment status can reproduce the response of consumption to such change in employment to a great extent. We also find that the most important factor behind such consumption changes is the wage difference between regular and irregular workers.