A valve unit comprising: a valve housing including: a supply oil passage configured to receive operating oil from a hydraulic pump, and a pressure adjustment valve (Va) configured to adjust a pressure of the supply oil passage, wherein the pressure adjustment valve (Va) includes: a pressure adjustment valve body configured to open and close the supply oil passage; a compression coil spring applying, to the pressure adjustment valve body, an urging force that keeps the pressure adjustment valve body at a closed position when the pressure of the supply oil passage is smaller than a set value and that allows the pressure adjustment valve body to open when the pressure of the supply oil passage is not smaller than the set value; and a restriction member configured to, when the pressure adjustment valve body becomes open against the urging force of the spring in response to a pressure of the operating oil, abut against the pressure adjustment valve body in such a manner as to restrict movement of the pressure adjustment valve body, wherein the valve housing includes a pump port through which the operating oil is configured to be supplied from the hydraulic pump to the supply oil passage, and a discharge port through which the operating oil downstream of the pressure adjustment valve (Va) in the supply oil passage is configured to be discharged, characterized in that the valve housing includes a branch oil passage (56, 57) that is branched out of the supply oil passage and that is configured to receive the operating oil upstream of the pressure adjustment valve (Va) in the supply oil passage, the valve housing has a control port (53, 54) through which the operating oil from the branch oil passage (56, 57) exits, and there is provided a solenoid valve that is configured to electromagnetically open and close the branch oil passage (56, 57). a valve housing including: a supply oil passage configured to receive operating oil from a hydraulic pump, and a pressure adjustment valve (Va) configured to adjust a pressure of the supply oil passage, wherein the pressure adjustment valve (Va) includes: a pressure adjustment valve body configured to open and close the supply oil passage; a compression coil spring applying, to the pressure adjustment valve body, an urging force that keeps the pressure adjustment valve body at a closed position when the pressure of the supply oil passage is smaller than a set value and that allows the pressure adjustment valve body to open when the pressure of the supply oil passage is not smaller than the set value; and a restriction member configured to, when the pressure adjustment valve body becomes open against the urging force of the spring in response to a pressure of the operating oil, abut against the pressure adjustment valve body in such a manner as to restrict movement of the pressure adjustment valve body, a pressure adjustment valve body configured to open and close the supply oil passage; a compression coil spring applying, to the pressure adjustment valve body, an urging force that keeps the pressure adjustment valve body at a closed position when the pressure of the supply oil passage is smaller than a set value and that allows the pressure adjustment valve body to open when the pressure of the supply oil passage is not smaller than the set value; and a restriction member configured to, when the pressure adjustment valve body becomes open against the urging force of the spring in response to a pressure of the operating oil, abut against the pressure adjustment valve body in such a manner as to restrict movement of the pressure adjustment valve body, wherein the valve housing includes a pump port through which the operating oil is configured to be supplied from the hydraulic pump to the supply oil passage, and a discharge port through which the operating oil downstream of the pressure adjustment valve (Va) in the supply oil passage is configured to be discharged, characterized in that the valve housing includes a branch oil passage (56, 57) that is branched out of the supply oil passage and that is configured to receive the operating oil upstream of the pressure adjustment valve (Va) in the supply oil passage, the valve housing has a control port (53, 54) through which the operating oil from the branch oil passage (56, 57) exits, and there is provided a solenoid valve that is configured to electromagnetically open and close the branch oil passage (56, 57).