PURPOSE: To provide a picture forming microcapsule which is not erroneously broken in the device and capable of liberating the core material with a smaller amt. of external force and to furnish a compact and lightweight picture forming device using the microcapsule.

CONSTITUTION: This picture forming microcapsule is a microcapsule 1 obtained by encapsulating a core material 3 consisting of at least a picture forming material 5 of pigment, etc., and a photosensitive material 4 with the wall members 2a and 2b of resin, etc., and the wall members 2a and 2b are formed with ≥2 kinds of materials having a different thermal expansion coefficient. The picture forming device uses the microcapsule and is provided with a means for breaking the capsule to liberate the core material 3 from the microcapsule 1, and a mechanism for heating the microcapsule 1 is furnished to the breaking means.