The D0-brane matrix model is conjectured to be a nonperturbative formulation of type IIA superstring theory and M-theory. This talk shows the latest results of numerical simulations of the D0-brane matrix model. The duality between the matrix model and type IIA superstring theory is confirmed with good precision, including stringy corrections. Furthermore, we find a new low-energy phase (confined phase) and suggest that this phase describes M-theory. We further argue that the matrix model can explain the eleven-dimensional Schwarzschild black hole.