An imprint apparatus forms a pattern by curing a radical polymerizable imprint material by irradiating the imprint material with light in a state in which a mold is brought into contact with the imprint material. The apparatus includes an irradiator configured to irradiate the imprint material with light, and a controller configured to control the irradiator. Letting Ic be an illuminance of the light with which the imprint material is irradiated, tc be a time during which the imprint material is irradiated with the light, k be a coefficient, and PD be a target degree of photopolymerization of the imprint material subjected to irradiation with the light, the controller determines the irradiation time in accordance with: PD=k×(√Ic)×tc.