Side-release buckle

A side-release buckle, comprising:

• a plug;
• and
• a socket for inserting and engaging the plug,
• the plug comprising a first parting line, a base portion having a first belt mounting portion, a pair of leg portions protruding from the base portion, and an engaging portion formed on each of the leg portions,
• the engaging portion comprising an engaging surface,
• the first belt mounting portion comprising an insertion hole for inserting a belt, and a first belt winding portion traversing the insertion hole at a position offset with respect to a first mold mating surface defined by the first parting line,
• the socket comprising a second parting line, a main body having a second belt mounting portion and an insertion port, a housing space formed in the main body and capable of housing the leg portions inserted from the insertion port, and a portion to be engaged formed on the main body and engageable with the engaging portion, and
• the portion to be engaged comprising a surface to be engaged that faces the engaging surface when engaged with the engaging portion,
• wherein, when a cross section of the engaging surface is observed from a direction that is an in-plane direction of the first mold mating surface defined by the first parting line of the plug and is also a direction perpendicular to an insertion direction, the engaging surface is located on an opposite side to the first belt winding portion with respect to the first mold mating surface, and has a first engaging surface forming with the first mold mating surface an angle A1 of 87° or more and 90° or less.