PURPOSE: To provide a capsule capable of releasing the enclosed substance by heating with a high degree of stability by forming said capsule of a urea or melamine resin containing a predetermined amount of a thermoplastic resin used as a wall membrane and enclosing a hydrophobic substance therein.

CONSTITUTION: The subject capsule is formed with the wall membrane of a urea of melamine resin containing not less than 40wt.% of a thermoplastic resin such as the emulsion of vinylidene chloride resin. The hydrophobic substance such as alkyl naphthalene and pigment is dispersed in the aqueous solution of prepolymer of urea or melamine resin, whereby the formation of the urea or melamine resin wall membrane is commenced around such hydrophobic substance and a thermoplastic resin dispersion medium is then added thereto. The resulting wall membrane of the capsule has resistances to thermoplasticity, heat, water and oil and releases the enclosed substance by heating.