An oil supply device for an engine is provided with a cylinder block, a shaft support member that bears the crank journal of a crankshaft together with a journal support wall section, and a nozzle that is fixed to the ceiling section of a crank chamber and that sprays oil on a piston which slides within a cylinder. The cylinder block is provided with: a first oil supply path that extends in a cylinder row direction at a position on one side section of the cylinder in a width direction that is orthogonal to the cylinder row direction; a branching oil path that branches from the first oil path at the position of the journal support wall section and that supplies oil to a crankshaft bearing section which bears the crank journal; and a second oil path that that supplies oil to the nozzle and that extends in the cylinder row direction at a position more to the outside in the width direction than the first oil path.