Sheet supply device

A sheet supply device comprising:

• a sheet supply tray on which sheets are stacked;
• a guide fence for restricting positions of the sheets along a sheet width direction perpendicular to a sheet supply direction;
• a slider block that is slidable along the sheet width direction and supports the guide fence in an upright state;
• a slide shaft that is inserted into a through hole formed in the slider block and guides sliding of the slider block along the sheet width direction;
• and
• a guide fence lock mechanism including a restriction member on which a hole is formed and that is attached to the slider block swingably at a position distanced from the guide fence, the slide shaft being inserted into the hole, wherein
• the guide fence lock mechanism is configured to restrict sliding of the slider block along the sheet width direction by holding the restriction member in a lock state where an inner circumferential edge of the hole is pushed onto an outer circumference of the slide shaft, and to allow sliding of the slider block along the sheet width direction when the restriction member is swung to cancel the lock state.