[PROBLEMS] To prevent or reduce the problem wherein color development and fading in expected color tones do not occur in an optical element that includes a photochromic coat layer containing alkylamino group-containing photochromic compounds and/or dialkylamino group-containing photochromic compounds in a high concentration and a hard coat layer formed on the photochromic coat layer. [MEANS FOR SOLVING PROBLEMS] A photochromic optical element comprising an optical substrate, a photochromic coat layer, and a hard coat layer that are laminated in this order, wherein (I) the photochromic coat layer comprising an alkylamino group-containing photochromic compound and/or a dialkylamino group-containing photochromic compound in a total amount of 0.1 to 10.0% by mass, and (II) the hard coat layer is obtained by curing a hard coat agent comprising metal oxide fine particles and an organosilicon compound, the hard coat agent containing as the organosilicon compound at least one selected from the group consisting of a tetraalkoxy silane, a methyl trialkoxy silane, and partial hydrolysates thereof in an amount of 10 to 60% by mass based on the total mass of the metal oxide fine particles and the organosilicon compound (with the proviso that, when the organosilicon compound is a partial hydrolysate of a partially hydrolyzable organosilicon compound, the mass of the organosilicon compound in the above total mass is the mass of the partially hydrolyzable organosilicon compound).