VARIABLE COMPRESSION-RATIO DEVICE

An object is to provide oil supply to a variable compression-ratio device. A variable compression-ratio device includes: a gear shaft (52) disposed inside a crankshaft (12) of an internal combustion engine (11) coaxially with the crankshaft (12) and configured to be rotationally driven by a power source (32); an input gear (51) connected to the gear shaft (52); an intermediate gear (50) supported by a crank web (16) of the crankshaft (12) and engaged with the input gear (51); an eccentric cam (31) disposed between a crank pin (17) of the crankshaft (12) and a large end (18a) of a connecting rod (18) and engaged with the intermediate gear (50); and a first oil channel (5) configured to supply lubricating oil to the input gear (51).