particles of a squarylium coloring agent represented by Formula (1);

a radically polymerizable monomer;

a radical polymerization initiator; and

a coloring agent sensitizer,

wherein a volume average particle diameter of the particles of the squarylium coloring agent is 10 nm to 400 nm,

wherein in Formula (1), a ring A and a ring B each independently represent an aromatic ring or a heteroaromatic ring, X^A and X^B each independently represent a monovalent substituent, G^A and G^B each independently represent a monovalent substituent, kA represents an integer of 0 to nA, kB represents an integer of 0 to nB, nA represents an integer that is a maximum number of G^A the ring A can have as its substituent, nB represents an integer that is a maximum number of G^B the ring B can have as its substituent, X^A and G^A or X^B and G^B may be bonded to each other to form a ring, and in a case where a plurality of G^A's or a plurality of G^B's are present, the plurality of G^A's bonded to the ring A and the plurality of G^B's bonded to the ring B may be bonded to each other to form a ring structure,

wherein a ratio of a content of the coloring agent sensitizer to a content of the squarylium coloring agent is in a range of from 1 to 20 on a mass basis, and

wherein a content of the coloring agent sensitizer in the photocurable ink composition is from 1.0% by mass to 15.0% by mass with respect to a total amount of the photocurable ink composition.