Lock mechanism and connector set

A lock mechanism configured to hold a fitted state between a first connector and a second connector, the first connector and the second connector as a counterpart being fittable together, the lock mechanism comprising:

• a lock member that includes an engagement part and is provided in the first connector;
• a biasing part that is connected to the lock member and holds the lock member in a reference state;
• a pivotal shaft that is disposed parallel to a direction orthogonal to a fitting direction and pivotably supports the lock member;
• an engagement-receiving part that is provided in the second connector and is engageable with the engagement part, and
• a removal operation member that is connected to the lock member and is pullable in a removal direction orthogonal to an extending direction of the pivotal shaft, wherein
• the lock member is attached to the first connector so as to be pivotable around the pivotal shaft,
• one of the removal operation member and the lock member includes an inclined surface formed to be inclined with respect to the removal direction,
• the other of the removal operation member and the lock member includes an engagement piece that engages with the inclined surface,
• a cam is formed by engagement between the inclined surface and the engagement piece, the cam converting a linear motion of the removal operation member into a rotational motion and transmits the rotational motion to the lock member, and
• a linear motion of the removal operation member in the removal direction causes a first moment to be generated, the first moment rotating the lock member around the pivotal shaft.