There is provided an active material-exfoliated graphite composite that allows a lithium ion secondary battery to be obtained in which the initial capacity is large and deterioration in charge and discharge cycle characteristics is less likely to occur, when used for a negative electrode material for lithium ion secondary batteries. An active material-exfoliated graphite composite comprising: partially exfoliated graphite having a structure in which graphite is partially exfoliated; and an active material that is in the form of particles capable of intercalating and deintercalating lithium ions by composite formation with the partially exfoliated graphite, or particles capable of adsorbing and desorbing lithium ions by composite formation with the partially exfoliated graphite, wherein the active material has an average particle diameter of 1 μm or more and 100 μm or less.