Kazuki Hiroe Title: Invariants of differential equations and algebraic curves Abstract: From algebraic differential equations on Riemann surfaces, we can define algebraic curves which we will call spectral curves. I will explain that structures of singularities of these algebraic curves have a close connection with those of irregular singularities of differential equations. In particular, I will make comparisons between (1) Milnor number & Komatsu-Malgrange irregularity, (2) blow up & Fourier transform, (3) knot structure & Stokes phenomenon, (4) cohomology of curves & de Rham cohomology of differential equations, and so on.